transfer of four protons from the matrix to the intermembrane space is an endergonic process

TLS Online TPP Program

#Id: 9057

#Unit 4. Cell Communication and Cell Signaling

glutamate (E200) and arginine (R209) participate in binding of cAMP, which causes a conformational change in the loop that prevents binding of the loop to the C subunit.

TLS Online TPP Program

#Id: 9058

#Unit 4. Cell Communication and Cell Signaling

Epinephrine --> Gαs-GTP-->Adenylyl cyclase-->cAMP-->PKA

TLS Online TPP Program

#Id: 9059

#Unit 4. Cell Communication and Cell Signaling

PKA always phosphorylates a serine or threonine residue that is located within the common sequence motif: X-Arg-(Arg/Lys)-X-(Ser/Thr)-Φ

TLS Online TPP Program

#Id: 9060

#Unit 4. Cell Communication and Cell Signaling

Increased cAMP; PKA active, increased glycogen breakdown, and decreased glycogen synthesis

TLS Online TPP Program

#Id: 9061

#Unit 4. Cell Communication and Cell Signaling

The GPK in skeletal muscle is a huge protein with multiple subunits:

Kinase subunit contains the catalytic activity that activates GP 

Regulatory subunits is the ubiquitous protein calmodulin

TLS Online TPP Program

#Id: 9062

#Unit 4. Cell Communication and Cell Signaling

GPK enzyme activity is increased either by phosphorylation of these two regulatory subunits by PKA or by Ca+2 binding to the calmodulin subunit; maximal activity requires both.