Binding of cAMP by an R subunit of PKA occurs in a cooperative fashion; i.e., binding of the first cAMP molecule to CNB-B lowers the Kd for binding of the second cAMP to CNB-A.

TLS Online TPP Program

#Id: 8610

#XL - T Zoology

TLS Online TPP Program

#Id: 8611

#XL - T Zoology

Nonphosphorylated CDK bound to one of its cyclin partners has minimal but detectable protein kinase activity in vitro, although it may be essentially inactive in vivo.

TLS Online TPP Program

#Id: 8612

#XL - T Zoology

Phosphorylation of a critical threonine residue in the activation loop, Thr-160, allowing substrates to access the active site of the CDK

TLS Online TPP Program

#Id: 8613

#XL - T Zoology

Threonine -160 phosphorylation is mediated by 

CDK-activating kinase (CAK)

TLS Online TPP Program

#Id: 8614

#XL - T Zoology

Two inhibitory phosphorylations on CDK play a critical role in controlling CDK activity:

Y15

T14

TLS Online TPP Program

#Id: 8615

#XL - T Zoology

Y15 & T14 are situated in the G-loop of the CDK, containing the consensus sequence GEGT14Y15GVV