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PMID |
Sentence |
1 |
9054447
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Specific increase in p85alpha expression in response to dexamethasone is associated with inhibition of insulin-like growth factor-I stimulated phosphatidylinositol 3-kinase activity in cultured muscle cells.
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2 |
9054447
|
The stimulation of phosphatidylinositol (PI) 3-kinase by insulin-like growth factor I (IGF-I) in L6 cultured skeletal muscle cells is inhibited by the glucocorticoid dexamethasone.
|
3 |
9054447
|
The objective of this study was to investigate the mechanism of dexamethasone action by determining its effects on the expression of the p85alpha and p85beta regulatory subunit isoforms of PI 3-kinase, their coupling with the p110 catalytic subunit, and their association with insulin receptor substrate 1 (IRS-1) in response to IGF-I stimulation.
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4 |
9054447
|
Dexamethasone induced a 300% increase in p85alpha protein content in the L6 cultured myoblast cell line, whereas it increased p110 content by only 38% and had no effect on p85beta.
|
5 |
9054447
|
Stimulation with IGF-I induced the association of p85alpha and p85beta with IRS-1, and this was accompanied by increased amounts of the p110 catalytic subunit and markedly increased PI 3-kinase activity in IRS-1 immunoprecipitates.
|
6 |
9054447
|
In cells treated with dexamethasone, greater amounts of p85alpha and lower amounts of p85beta, respectively, were found in IRS-1 immunoprecipitates, such that the alpha/beta ratio was markedly higher than in control cells.
|
7 |
9054447
|
In spite of the increase in both total and IRS-1-associated p85alpha following dexamethasone treatment, IRS-1-associated p110 catalytic subunit and PI 3-kinase activity were decreased by approximately 50%.
|
8 |
9054447
|
Thus, dexamethasone induces a specific increase in expression of the p85alpha regulatory subunit that is not associated with a coordinate increase in the p110 catalytic subunit of PI 3-kinase.
|
9 |
9054447
|
As a consequence, in dexamethasone-treated cells, p85alpha that is not coupled with p110 competes with both p85alpha.p110 and p85beta.p110 complexes for association with IRS-1, leading to increased p85alpha but decreased p85beta, p110, and PI 3-kinase activity in IRS-1 immunoprecipitates.
|
10 |
9054447
|
Specific increase in p85alpha expression in response to dexamethasone is associated with inhibition of insulin-like growth factor-I stimulated phosphatidylinositol 3-kinase activity in cultured muscle cells.
|
11 |
9054447
|
The stimulation of phosphatidylinositol (PI) 3-kinase by insulin-like growth factor I (IGF-I) in L6 cultured skeletal muscle cells is inhibited by the glucocorticoid dexamethasone.
|
12 |
9054447
|
The objective of this study was to investigate the mechanism of dexamethasone action by determining its effects on the expression of the p85alpha and p85beta regulatory subunit isoforms of PI 3-kinase, their coupling with the p110 catalytic subunit, and their association with insulin receptor substrate 1 (IRS-1) in response to IGF-I stimulation.
|
13 |
9054447
|
Dexamethasone induced a 300% increase in p85alpha protein content in the L6 cultured myoblast cell line, whereas it increased p110 content by only 38% and had no effect on p85beta.
|
14 |
9054447
|
Stimulation with IGF-I induced the association of p85alpha and p85beta with IRS-1, and this was accompanied by increased amounts of the p110 catalytic subunit and markedly increased PI 3-kinase activity in IRS-1 immunoprecipitates.
|
15 |
9054447
|
In cells treated with dexamethasone, greater amounts of p85alpha and lower amounts of p85beta, respectively, were found in IRS-1 immunoprecipitates, such that the alpha/beta ratio was markedly higher than in control cells.
|
16 |
9054447
|
In spite of the increase in both total and IRS-1-associated p85alpha following dexamethasone treatment, IRS-1-associated p110 catalytic subunit and PI 3-kinase activity were decreased by approximately 50%.
|
17 |
9054447
|
Thus, dexamethasone induces a specific increase in expression of the p85alpha regulatory subunit that is not associated with a coordinate increase in the p110 catalytic subunit of PI 3-kinase.
|
18 |
9054447
|
As a consequence, in dexamethasone-treated cells, p85alpha that is not coupled with p110 competes with both p85alpha.p110 and p85beta.p110 complexes for association with IRS-1, leading to increased p85alpha but decreased p85beta, p110, and PI 3-kinase activity in IRS-1 immunoprecipitates.
|
19 |
9054447
|
Specific increase in p85alpha expression in response to dexamethasone is associated with inhibition of insulin-like growth factor-I stimulated phosphatidylinositol 3-kinase activity in cultured muscle cells.
|
20 |
9054447
|
The stimulation of phosphatidylinositol (PI) 3-kinase by insulin-like growth factor I (IGF-I) in L6 cultured skeletal muscle cells is inhibited by the glucocorticoid dexamethasone.
|
21 |
9054447
|
The objective of this study was to investigate the mechanism of dexamethasone action by determining its effects on the expression of the p85alpha and p85beta regulatory subunit isoforms of PI 3-kinase, their coupling with the p110 catalytic subunit, and their association with insulin receptor substrate 1 (IRS-1) in response to IGF-I stimulation.
|
22 |
9054447
|
Dexamethasone induced a 300% increase in p85alpha protein content in the L6 cultured myoblast cell line, whereas it increased p110 content by only 38% and had no effect on p85beta.
|
23 |
9054447
|
Stimulation with IGF-I induced the association of p85alpha and p85beta with IRS-1, and this was accompanied by increased amounts of the p110 catalytic subunit and markedly increased PI 3-kinase activity in IRS-1 immunoprecipitates.
|
24 |
9054447
|
In cells treated with dexamethasone, greater amounts of p85alpha and lower amounts of p85beta, respectively, were found in IRS-1 immunoprecipitates, such that the alpha/beta ratio was markedly higher than in control cells.
|
25 |
9054447
|
In spite of the increase in both total and IRS-1-associated p85alpha following dexamethasone treatment, IRS-1-associated p110 catalytic subunit and PI 3-kinase activity were decreased by approximately 50%.
|
26 |
9054447
|
Thus, dexamethasone induces a specific increase in expression of the p85alpha regulatory subunit that is not associated with a coordinate increase in the p110 catalytic subunit of PI 3-kinase.
|
27 |
9054447
|
As a consequence, in dexamethasone-treated cells, p85alpha that is not coupled with p110 competes with both p85alpha.p110 and p85beta.p110 complexes for association with IRS-1, leading to increased p85alpha but decreased p85beta, p110, and PI 3-kinase activity in IRS-1 immunoprecipitates.
|
28 |
9054447
|
Specific increase in p85alpha expression in response to dexamethasone is associated with inhibition of insulin-like growth factor-I stimulated phosphatidylinositol 3-kinase activity in cultured muscle cells.
|
29 |
9054447
|
The stimulation of phosphatidylinositol (PI) 3-kinase by insulin-like growth factor I (IGF-I) in L6 cultured skeletal muscle cells is inhibited by the glucocorticoid dexamethasone.
|
30 |
9054447
|
The objective of this study was to investigate the mechanism of dexamethasone action by determining its effects on the expression of the p85alpha and p85beta regulatory subunit isoforms of PI 3-kinase, their coupling with the p110 catalytic subunit, and their association with insulin receptor substrate 1 (IRS-1) in response to IGF-I stimulation.
|
31 |
9054447
|
Dexamethasone induced a 300% increase in p85alpha protein content in the L6 cultured myoblast cell line, whereas it increased p110 content by only 38% and had no effect on p85beta.
|
32 |
9054447
|
Stimulation with IGF-I induced the association of p85alpha and p85beta with IRS-1, and this was accompanied by increased amounts of the p110 catalytic subunit and markedly increased PI 3-kinase activity in IRS-1 immunoprecipitates.
|
33 |
9054447
|
In cells treated with dexamethasone, greater amounts of p85alpha and lower amounts of p85beta, respectively, were found in IRS-1 immunoprecipitates, such that the alpha/beta ratio was markedly higher than in control cells.
|
34 |
9054447
|
In spite of the increase in both total and IRS-1-associated p85alpha following dexamethasone treatment, IRS-1-associated p110 catalytic subunit and PI 3-kinase activity were decreased by approximately 50%.
|
35 |
9054447
|
Thus, dexamethasone induces a specific increase in expression of the p85alpha regulatory subunit that is not associated with a coordinate increase in the p110 catalytic subunit of PI 3-kinase.
|
36 |
9054447
|
As a consequence, in dexamethasone-treated cells, p85alpha that is not coupled with p110 competes with both p85alpha.p110 and p85beta.p110 complexes for association with IRS-1, leading to increased p85alpha but decreased p85beta, p110, and PI 3-kinase activity in IRS-1 immunoprecipitates.
|
37 |
9054447
|
Specific increase in p85alpha expression in response to dexamethasone is associated with inhibition of insulin-like growth factor-I stimulated phosphatidylinositol 3-kinase activity in cultured muscle cells.
|
38 |
9054447
|
The stimulation of phosphatidylinositol (PI) 3-kinase by insulin-like growth factor I (IGF-I) in L6 cultured skeletal muscle cells is inhibited by the glucocorticoid dexamethasone.
|
39 |
9054447
|
The objective of this study was to investigate the mechanism of dexamethasone action by determining its effects on the expression of the p85alpha and p85beta regulatory subunit isoforms of PI 3-kinase, their coupling with the p110 catalytic subunit, and their association with insulin receptor substrate 1 (IRS-1) in response to IGF-I stimulation.
|
40 |
9054447
|
Dexamethasone induced a 300% increase in p85alpha protein content in the L6 cultured myoblast cell line, whereas it increased p110 content by only 38% and had no effect on p85beta.
|
41 |
9054447
|
Stimulation with IGF-I induced the association of p85alpha and p85beta with IRS-1, and this was accompanied by increased amounts of the p110 catalytic subunit and markedly increased PI 3-kinase activity in IRS-1 immunoprecipitates.
|
42 |
9054447
|
In cells treated with dexamethasone, greater amounts of p85alpha and lower amounts of p85beta, respectively, were found in IRS-1 immunoprecipitates, such that the alpha/beta ratio was markedly higher than in control cells.
|
43 |
9054447
|
In spite of the increase in both total and IRS-1-associated p85alpha following dexamethasone treatment, IRS-1-associated p110 catalytic subunit and PI 3-kinase activity were decreased by approximately 50%.
|
44 |
9054447
|
Thus, dexamethasone induces a specific increase in expression of the p85alpha regulatory subunit that is not associated with a coordinate increase in the p110 catalytic subunit of PI 3-kinase.
|
45 |
9054447
|
As a consequence, in dexamethasone-treated cells, p85alpha that is not coupled with p110 competes with both p85alpha.p110 and p85beta.p110 complexes for association with IRS-1, leading to increased p85alpha but decreased p85beta, p110, and PI 3-kinase activity in IRS-1 immunoprecipitates.
|
46 |
9054447
|
Specific increase in p85alpha expression in response to dexamethasone is associated with inhibition of insulin-like growth factor-I stimulated phosphatidylinositol 3-kinase activity in cultured muscle cells.
|
47 |
9054447
|
The stimulation of phosphatidylinositol (PI) 3-kinase by insulin-like growth factor I (IGF-I) in L6 cultured skeletal muscle cells is inhibited by the glucocorticoid dexamethasone.
|
48 |
9054447
|
The objective of this study was to investigate the mechanism of dexamethasone action by determining its effects on the expression of the p85alpha and p85beta regulatory subunit isoforms of PI 3-kinase, their coupling with the p110 catalytic subunit, and their association with insulin receptor substrate 1 (IRS-1) in response to IGF-I stimulation.
|
49 |
9054447
|
Dexamethasone induced a 300% increase in p85alpha protein content in the L6 cultured myoblast cell line, whereas it increased p110 content by only 38% and had no effect on p85beta.
|
50 |
9054447
|
Stimulation with IGF-I induced the association of p85alpha and p85beta with IRS-1, and this was accompanied by increased amounts of the p110 catalytic subunit and markedly increased PI 3-kinase activity in IRS-1 immunoprecipitates.
|
51 |
9054447
|
In cells treated with dexamethasone, greater amounts of p85alpha and lower amounts of p85beta, respectively, were found in IRS-1 immunoprecipitates, such that the alpha/beta ratio was markedly higher than in control cells.
|
52 |
9054447
|
In spite of the increase in both total and IRS-1-associated p85alpha following dexamethasone treatment, IRS-1-associated p110 catalytic subunit and PI 3-kinase activity were decreased by approximately 50%.
|
53 |
9054447
|
Thus, dexamethasone induces a specific increase in expression of the p85alpha regulatory subunit that is not associated with a coordinate increase in the p110 catalytic subunit of PI 3-kinase.
|
54 |
9054447
|
As a consequence, in dexamethasone-treated cells, p85alpha that is not coupled with p110 competes with both p85alpha.p110 and p85beta.p110 complexes for association with IRS-1, leading to increased p85alpha but decreased p85beta, p110, and PI 3-kinase activity in IRS-1 immunoprecipitates.
|
55 |
10868937
|
Inhibitory effect of IGF-I on type 2 nitric oxide synthase expression in Ins-1 cells and protection against activation-dependent apoptosis: involvement of phosphatidylinositol 3-kinase.
|
56 |
10868937
|
Challenge of Ins-1 cells, a rat beta-pancreatic cell line, with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) promoted the expression of type 2 nitric oxide synthase (NOS-2) in a cooperative way.
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57 |
10868937
|
Treatment of Ins-1 cells with IGF-I significantly inhibited the expression of NOS-2, especially at subsaturating concentrations of LPS and IFN-gamma.
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58 |
10868937
|
The inhibitory effect of IGF-I on NOS-2 expression was abrogated when cells were incubated with wortmannin or LY294002, two inhibitors of phosphatidylinositol 3-kinase.
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59 |
10868937
|
Transient expression of the p110 subunit of phosphatidylinositol 3-kinase impaired the LPS and IFN-gamma-dependent NOS-2 promoter activity in cells transfected with a 1-kb fragment corresponding to the 5'-flanking region of the NOS-2 gene.
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60 |
10868937
|
However, expression of a dominant negative form of p85 abolished the inhibitory action of IGF-I on the NOS-2 promoter activity.
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61 |
10868937
|
However, in activated cells treated with N-[3-(aminomethyl)benzyl]acetamidine, a specific NOS-2 inhibitor, IGF-I completely abolished the NO-independent apoptosis.
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62 |
11549666
|
Insulin stimulation of glycogen synthase activity as well as phosphorylation of MAPK, p70 S6 kinase, and protein kinase B (Akt) were blocked by the phosphatidylinositol 3-kinase inhibitors wortmannin (50 nM) and LY294002 (10 microM).
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63 |
11549666
|
This increased sensitivity of diabetic muscle to impairment of insulin-stimulated glycogen synthase activity occurs together with diminished insulin-stimulation (by 40%) of IRS-1-associated phosphatidylinositol 3-kinase activity in the same cells.
|
64 |
11549666
|
Protein expression of IRS-1, p85, p110, Akt, p70 S6 kinase, and MAPK were normal in diabetic cells, as was insulin-stimulated phosphorylation of Akt, p70 S6 kinase, and MAPK.
|
65 |
11549666
|
These studies indicate that, despite prolonged growth and differentiation of diabetic muscle under normal metabolic culture conditions, defects of insulin-stimulated phosphatidylinositol 3-kinase and glycogen synthase activity in diabetic muscle persist, consistent with intrinsic (rather than acquired) defects of insulin action.
|
66 |
11784871
|
Class Ia phosphoinositide (PI) 3-kinase is a central component in growth factor signaling and is comprised of a p110 catalytic subunit and a regulatory subunit, the most common family of which is derived from the p85alpha gene (Pik3r1).
|
67 |
11784871
|
In wild-type cells, the p85 subunit is more abundant than p110, leading to competition between the p85 monomer and the p85-p110 dimer and ineffective signaling.
|
68 |
11784871
|
Heterozygous disruption of Pik3r1 results in increased Akt activity and decreased apoptosis by insulin-like growth factor 1 (IGF-1) through up-regulated phosphatidylinositol (3,4,5)-triphosphate production.
|
69 |
11784871
|
Thus, a reduction in p85alpha represents a novel therapeutic target for enhancing IGF-1/insulin signaling, prolongation of cell survival, and protection against apoptosis.
|
70 |
11784871
|
Class Ia phosphoinositide (PI) 3-kinase is a central component in growth factor signaling and is comprised of a p110 catalytic subunit and a regulatory subunit, the most common family of which is derived from the p85alpha gene (Pik3r1).
|
71 |
11784871
|
In wild-type cells, the p85 subunit is more abundant than p110, leading to competition between the p85 monomer and the p85-p110 dimer and ineffective signaling.
|
72 |
11784871
|
Heterozygous disruption of Pik3r1 results in increased Akt activity and decreased apoptosis by insulin-like growth factor 1 (IGF-1) through up-regulated phosphatidylinositol (3,4,5)-triphosphate production.
|
73 |
11784871
|
Thus, a reduction in p85alpha represents a novel therapeutic target for enhancing IGF-1/insulin signaling, prolongation of cell survival, and protection against apoptosis.
|
74 |
14504291
|
Positive and negative roles of p85 alpha and p85 beta regulatory subunits of phosphoinositide 3-kinase in insulin signaling.
|
75 |
14504291
|
Class IA phosphoinositide (PI) 3-kinase is composed of a p110 catalytic subunit and a p85 regulatory subunit and plays a pivotal role in insulin signaling.
|
76 |
14504291
|
To explore the physiological roles of two major regulatory isoforms, p85 alpha and p85 beta, we have established brown adipose cell lines with disruption of the Pik3r1 or Pik3r2 gene.
|
77 |
14504291
|
Pik3r1-/- (p85 alpha-/-) cells show a 70% reduction of p85 protein and a parallel reduction of p110.
|
78 |
14504291
|
These cells have a 50% decrease in PI 3-kinase activity and a 30% decrease in Akt activity, leading to decreased insulin-induced glucose uptake and anti-apoptosis.
|
79 |
14504291
|
Pik3r2-/- (p85 beta-/-) cells show a 25% reduction of p85 protein but normal levels of p85-p110 and PI 3-kinase activity, supporting the fact that p85 is more abundant than p110 in wild type. p85 beta-/- cells, however, exhibit significantly increased insulin-induced Akt activation, leading to increased anti-apoptosis.
|
80 |
14504291
|
Reconstitution experiments suggest that the discrepancy between PI 3-kinase activity and Akt activity is at least in part due to the p85-dependent negative regulation of downstream signaling of PI 3-kinase.
|
81 |
14504291
|
Indeed, both p85 alpha-/- cells and p85 beta-/- cells exhibit significantly increased insulin-induced glycogen synthase activation. p85 alpha-/- cells show decreased insulin-stimulated Jun N-terminal kinase activity, which is restored by expression of p85 alpha, p85 beta, or a p85 mutant that does not bind to p110, indicating the existence of p85-dependent, but PI 3-kinase-independent, signaling pathway.
|
82 |
14504291
|
Furthermore, a reduction of p85 beta specifically increases insulin receptor substrate-2 phosphorylation.
|
83 |
14504291
|
Thus, p85 alpha and p85 beta modulate PI 3-kinase-dependent signaling by multiple mechanisms and transmit signals independent of PI 3-kinase activation.
|
84 |
14504291
|
Positive and negative roles of p85 alpha and p85 beta regulatory subunits of phosphoinositide 3-kinase in insulin signaling.
|
85 |
14504291
|
Class IA phosphoinositide (PI) 3-kinase is composed of a p110 catalytic subunit and a p85 regulatory subunit and plays a pivotal role in insulin signaling.
|
86 |
14504291
|
To explore the physiological roles of two major regulatory isoforms, p85 alpha and p85 beta, we have established brown adipose cell lines with disruption of the Pik3r1 or Pik3r2 gene.
|
87 |
14504291
|
Pik3r1-/- (p85 alpha-/-) cells show a 70% reduction of p85 protein and a parallel reduction of p110.
|
88 |
14504291
|
These cells have a 50% decrease in PI 3-kinase activity and a 30% decrease in Akt activity, leading to decreased insulin-induced glucose uptake and anti-apoptosis.
|
89 |
14504291
|
Pik3r2-/- (p85 beta-/-) cells show a 25% reduction of p85 protein but normal levels of p85-p110 and PI 3-kinase activity, supporting the fact that p85 is more abundant than p110 in wild type. p85 beta-/- cells, however, exhibit significantly increased insulin-induced Akt activation, leading to increased anti-apoptosis.
|
90 |
14504291
|
Reconstitution experiments suggest that the discrepancy between PI 3-kinase activity and Akt activity is at least in part due to the p85-dependent negative regulation of downstream signaling of PI 3-kinase.
|
91 |
14504291
|
Indeed, both p85 alpha-/- cells and p85 beta-/- cells exhibit significantly increased insulin-induced glycogen synthase activation. p85 alpha-/- cells show decreased insulin-stimulated Jun N-terminal kinase activity, which is restored by expression of p85 alpha, p85 beta, or a p85 mutant that does not bind to p110, indicating the existence of p85-dependent, but PI 3-kinase-independent, signaling pathway.
|
92 |
14504291
|
Furthermore, a reduction of p85 beta specifically increases insulin receptor substrate-2 phosphorylation.
|
93 |
14504291
|
Thus, p85 alpha and p85 beta modulate PI 3-kinase-dependent signaling by multiple mechanisms and transmit signals independent of PI 3-kinase activation.
|
94 |
14504291
|
Positive and negative roles of p85 alpha and p85 beta regulatory subunits of phosphoinositide 3-kinase in insulin signaling.
|
95 |
14504291
|
Class IA phosphoinositide (PI) 3-kinase is composed of a p110 catalytic subunit and a p85 regulatory subunit and plays a pivotal role in insulin signaling.
|
96 |
14504291
|
To explore the physiological roles of two major regulatory isoforms, p85 alpha and p85 beta, we have established brown adipose cell lines with disruption of the Pik3r1 or Pik3r2 gene.
|
97 |
14504291
|
Pik3r1-/- (p85 alpha-/-) cells show a 70% reduction of p85 protein and a parallel reduction of p110.
|
98 |
14504291
|
These cells have a 50% decrease in PI 3-kinase activity and a 30% decrease in Akt activity, leading to decreased insulin-induced glucose uptake and anti-apoptosis.
|
99 |
14504291
|
Pik3r2-/- (p85 beta-/-) cells show a 25% reduction of p85 protein but normal levels of p85-p110 and PI 3-kinase activity, supporting the fact that p85 is more abundant than p110 in wild type. p85 beta-/- cells, however, exhibit significantly increased insulin-induced Akt activation, leading to increased anti-apoptosis.
|
100 |
14504291
|
Reconstitution experiments suggest that the discrepancy between PI 3-kinase activity and Akt activity is at least in part due to the p85-dependent negative regulation of downstream signaling of PI 3-kinase.
|
101 |
14504291
|
Indeed, both p85 alpha-/- cells and p85 beta-/- cells exhibit significantly increased insulin-induced glycogen synthase activation. p85 alpha-/- cells show decreased insulin-stimulated Jun N-terminal kinase activity, which is restored by expression of p85 alpha, p85 beta, or a p85 mutant that does not bind to p110, indicating the existence of p85-dependent, but PI 3-kinase-independent, signaling pathway.
|
102 |
14504291
|
Furthermore, a reduction of p85 beta specifically increases insulin receptor substrate-2 phosphorylation.
|
103 |
14504291
|
Thus, p85 alpha and p85 beta modulate PI 3-kinase-dependent signaling by multiple mechanisms and transmit signals independent of PI 3-kinase activation.
|
104 |
14504291
|
Positive and negative roles of p85 alpha and p85 beta regulatory subunits of phosphoinositide 3-kinase in insulin signaling.
|
105 |
14504291
|
Class IA phosphoinositide (PI) 3-kinase is composed of a p110 catalytic subunit and a p85 regulatory subunit and plays a pivotal role in insulin signaling.
|
106 |
14504291
|
To explore the physiological roles of two major regulatory isoforms, p85 alpha and p85 beta, we have established brown adipose cell lines with disruption of the Pik3r1 or Pik3r2 gene.
|
107 |
14504291
|
Pik3r1-/- (p85 alpha-/-) cells show a 70% reduction of p85 protein and a parallel reduction of p110.
|
108 |
14504291
|
These cells have a 50% decrease in PI 3-kinase activity and a 30% decrease in Akt activity, leading to decreased insulin-induced glucose uptake and anti-apoptosis.
|
109 |
14504291
|
Pik3r2-/- (p85 beta-/-) cells show a 25% reduction of p85 protein but normal levels of p85-p110 and PI 3-kinase activity, supporting the fact that p85 is more abundant than p110 in wild type. p85 beta-/- cells, however, exhibit significantly increased insulin-induced Akt activation, leading to increased anti-apoptosis.
|
110 |
14504291
|
Reconstitution experiments suggest that the discrepancy between PI 3-kinase activity and Akt activity is at least in part due to the p85-dependent negative regulation of downstream signaling of PI 3-kinase.
|
111 |
14504291
|
Indeed, both p85 alpha-/- cells and p85 beta-/- cells exhibit significantly increased insulin-induced glycogen synthase activation. p85 alpha-/- cells show decreased insulin-stimulated Jun N-terminal kinase activity, which is restored by expression of p85 alpha, p85 beta, or a p85 mutant that does not bind to p110, indicating the existence of p85-dependent, but PI 3-kinase-independent, signaling pathway.
|
112 |
14504291
|
Furthermore, a reduction of p85 beta specifically increases insulin receptor substrate-2 phosphorylation.
|
113 |
14504291
|
Thus, p85 alpha and p85 beta modulate PI 3-kinase-dependent signaling by multiple mechanisms and transmit signals independent of PI 3-kinase activation.
|
114 |
16569213
|
Angiotensin II stimulates phosphorylation of an ectodomain-truncated platelet-derived growth factor receptor-beta and its binding to class IA PI3K in vascular smooth muscle cells.
|
115 |
16569213
|
PI3K (phosphoinositide 3-kinase) activity is involved in Ang (angiotensin) II-stimulated VSMC (vascular smooth muscle cell) growth and hypertrophy.
|
116 |
16569213
|
In the present study, we demonstrate that the inhibition of PI3K in VSMCs by expression of a dominant-negative p85alpha mutant lacking the p110-binding domain (Deltap85), or by treatment of cells with LY294002, inhibited Ang II-stimulated PAI-1 (plasminogen activator inhibitor-1) mRNA expression.
|
117 |
16569213
|
Using a GST (glutathione S-transferase) fusion protein containing the p85 N-terminal SH2 (Src homology 2) domain as 'bait' followed by MS/MS (tandem MS), we identified a 70 kDa fragment of the p70 PDGFR-beta (platelet-derived growth factor receptor-beta) as a signalling adapter that is phosphorylated and recruits the p85 subunit of PI3K after Ang II stimulation of AT1 (Ang II subtype 1) receptors on VSMCs.
|
118 |
16569213
|
Stimulation of VSMCs with Ang II increased tyrosine-phosphorylation of p70 PDGFR-beta at Tyr751 and Tyr1021 and increased its binding to p85.
|
119 |
16569213
|
PDGF also induced phosphorylation of p70 PDGFR-beta, a response inhibited by the PDGF tyrosine kinase selective inhibitor, AG1296.
|
120 |
16569213
|
Ang II-stimulated phosphorylation of the p70 PDGFR-beta was blocked by the AT1 receptor antagonist, candesartan (CV 11974) and was partially inhibited by PP2 {4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine}, an Src family kinase inhibitor.
|
121 |
16569213
|
Our result suggests that the p70 PDGFR-beta functions as an adapter that recruits PI3K to the membrane upon AT1 receptor stimulation.
|
122 |
17119157
|
PTEN regulation, a novel function for the p85 subunit of phosphoinositide 3-kinase.
|
123 |
17119157
|
Class I(A) phosphatidylinositol 3-kinase (PI3K), which is composed of a p85 (regulatory) and p110 (catalytic) subunits, is the enzyme generating PI(3,4)P2 and PI(3,4,5)P3 following GFR stimulation.
|
124 |
17119157
|
Examination of frequent genetic alterations in human cancer showed that PTEN (phosphatase with tensin homology on chromosome 10) is the major enzyme that decreases PI(3,4)P2 and PI(3,4,5)P3 cell content.
|
125 |
17119157
|
The recent description of diminished PTEN activity in liver-conditional knockout mice lacking the p85alpha PI3K regulatory subunit reveals a previously unknown p85alpha-dependent negative-feedback pathway that controls PI(3,4)P2 and PI(3,4,5)P3 half-life by regulating PTEN.
|
126 |
17827708
|
Role of phosphatidylinositol 3-kinase activation on insulin action and its alteration in diabetic conditions.
|
127 |
17827708
|
Activation of PI (phosphatidylinositol) 3-kinase is essential for aspects of insulin-induced glucose metabolism, including translocation of GLUT4 to the cell surface and glycogen synthesis.
|
128 |
17827708
|
The enzyme exists as a heterodimer containing a regulatory subunit and one of two widely-distributed isoforms of the p110 catalytic subunit: p110alpha or p110beta.
|
129 |
17827708
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Activation of PI 3-kinase and its downstream AKT has been demonstrated to be essential for almost all of the insulin-induced glucose and lipid metabolism such as glucose uptake, glycogen synthesis, suppression of glucose output and triglyceride synthesis as well as insulin-induced mitogenesis.
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130 |
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In the obesity-induced insulin resistant condition, JNK and p70S6K are activated and phosphorylate IRS-proteins, which diminishes the insulin-induced tyrosine phosphorylation of IRS-proteins and thereby impairs the PI 3-kinase/AKT activations.
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131 |
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Thus, the drugs which restore the impaired insulin-induced PI 3-kinase/AKT activation, for example, by suppressing JNK or p70S6K, PTEN or SHIP2, could be novel agents to treat diabetes mellitus.
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