The ER captures selected proteins from the cytosol as they are being synthesized. These are of two types:

Transmembrane proteins

Water-soluble proteins

TLS Online TPP Program

#Id: 8866

#XL - R Botany

TLS Online TPP Program

#Id: 8867

#XL - R Botany

Cdc25B is act as a starter phosphatase that initiates CDK1 activation

Cdc25C is the workhorse phosphatase that activates the vast majority of cyclin-CDK1 complexes

TLS Online TPP Program

#Id: 8868

#XL - R Botany

TLS Online TPP Program

#Id: 8869

#XL - R Botany

Yeast cells with a defective wee1+ gene activate mitotic CDKs prematurely and premature entry into mitosis (smaller than normal cells

TLS Online TPP Program

#Id: 8870

#XL - R Botany

Fission yeast cells carrying a CDK1 mutation in which the tyrosine-15 residue is replaced by phenylalanine

show the same premature mitotic CDK activation and entry into mitosis.

TLS Online TPP Program

#Id: 8871

#XL - R Botany

Until Mitotic CDKs is not active, the activatory protein phosphatase, Cdc25, is phosphorylated, bound and inhibited by phosphoserine/threonine-binding protein 14-3-3.