iP and tZ are active, and their derivatives are abundant, but they are susceptible to degradation by CK oxidase (CKX).

TLS Online TPP Program

#Id: 8870

#Unit 2. Cellular Organization

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

#Unit 2. Cellular Organization

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

TLS Online TPP Program

#Id: 8872

#Unit 2. Cellular Organization

The entire process of mitotic CDKs activation and entry into mitosis involves two positive feedback loops and coordination between events at the centrosome, in the cytoplasm, and in the nucleus.

TLS Online TPP Program

#Id: 8873

#Unit 2. Cellular Organization

Cdc25B, activating an initial small pool of cyclin B/1 at the centrosome, which is facilitate centrosome maturation.

TLS Online TPP Program

#Id: 8874

#Unit 2. Cellular Organization

Initial pool of active cyclin B-CDK1 phosphorylates Cdc25C, this recruits Pin1 and Plk1, which recognize Cdc25C through their phospho-binding domains. 

TLS Online TPP Program

#Id: 8875

#Unit 2. Cellular Organization

Pin1 and Plk1 modify and phosphorylate Cdc25C to stimulate its phosphatase activity