PD-1 has a structure similar to CTLA-4 and when activated negatively regulates T-cell function by inducing apoptosis of activated T cells. 

TLS Online TPP Program

#Id: 8646

#XL - T Zoology

One of the important substrates of the G1/S phase cyclin-CDK complexes is Cdh1.

TLS Online TPP Program

#Id: 8647

#XL - T Zoology

TLS Online TPP Program

#Id: 8648

#XL - T Zoology

During exit from mitosis and G1, 

Cdh1 is de-phosphorylated and APC/Ccdh1 is active.

TLS Online TPP Program

#Id: 8649

#XL - T Zoology

During S phase and mitosis, 

Cdh1 is phosphorylated, Cdh1 dissociates from APC/C, and APC/C becomes inactive.

TLS Online TPP Program

#Id: 8650

#XL - T Zoology

G1/S phase CDKs phosphorylate Cdh1 at the 

G1-S phase transition

TLS Online TPP Program

#Id: 8651

#XL - T Zoology

S phase cyclin-CDK accumulates in late G1 , they are immediately inactivated by binding of a CKI called Sic1