The SH3 domains in GRB2 selectively bind to 

proline-rich sequences in Sos

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#Unit 4. Cell Communication and Cell Signaling

Active PKB, phosphorylates

and inhibits the GTP→GDP hydrolysis activity of two GAP

proteins - AS160 and RGC

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#Unit 4. Cell Communication and Cell Signaling

Phosphorylation causes the binding of AS160 to the 

14-3-3 protein that sequesters it in the cytosol away from its target Rab proteins

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#Unit 4. Cell Communication and Cell Signaling

In the basal state, 

GAPs inhibit RalA and Rab10 function by enhancing their rates of GTP hydrolysis

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#Unit 4. Cell Communication and Cell Signaling

Phosphorylation of both GAPs by PKB allows RalA and the Rab10 to accumulate in their active GTP-bound states, enabling them to facilitate GSVs targeting and fusion

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#Unit 4. Cell Communication and Cell Signaling

In resting cells, 

GSK3 is catalytically active which phosphorylates and inhibits glycogen synthase, thus blocking glycogen synthesis from glucose

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#Unit 4. Cell Communication and Cell Signaling

In presence of insulin, 

GSK3 becomes phosphorylated by PKB its catalytic activity is inhibited