Upon absorbing UV-B photons, the tryptophans undergo structural changes that break the salt bridges, leading to the dissociation of the two functionally active monomers. The monomers then interact with COP1–SPA complexes to activate gene expression

TLS Online TPP Program

#Id: 8644

#XL - T Zoology

Phosphorylation on multiple sites by G1 CDKs blocks Rb from associating with E2F and promotes its export out of the nucleus.

TLS Online TPP Program

#Id: 8645

#XL - T Zoology

Rb protein regulation by G1 CDKs in mammalian cells is analogous to Whi5 regulation by Cln3-CDK in yeast.

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.