Constitutively active Ras proteins (RasD) 

Replacement of the normal glycine 12 with any other amino acid (except proline) blocks the functional binding of GAP proteins and in essence “locks” Ras in the active GTP-bound state.

TLS Online TPP Program

#Id: 9057

#XL - T Zoology

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

#XL - T Zoology

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

TLS Online TPP Program

#Id: 9059

#XL - T Zoology

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

#XL - T Zoology

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

TLS Online TPP Program

#Id: 9061

#XL - T Zoology

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

#XL - T Zoology

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.