Cyclins are degraded through the action of two different E3-ligases:

1. SCF (Skp1, Cullin, and F-box proteins) 

2. APC/C or cyclosome

TLS Online TPP Program

#Id: 8622

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Cyclins are degraded through the action of two different E3-ligases:

1. SCF (Skp1, Cullin, and F-box proteins) 

2. APC/C or cyclosome

TLS Online TPP Program

#Id: 8642

#XL - R Botany

TLS Online TPP Program

#Id: 8643

#XL - R Botany

When E2Fs are bound to Rb, not only are they transcriptionally inactive, but they also function to repress transcription by recruiting chromatin-modifying enzymes that promote deacetylation and methylation of specific histone lysines.

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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 - R Botany

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 - R Botany

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

TLS Online TPP Program

#Id: 8647

#XL - R Botany