Wee1

Wee1
Crystal structure of human Wee1
Identifiers
Symbol	Mitosis inhibitor protein kinase Wee1
Alt. symbols	wee1 dual specificity protein kinase Wee1
Entrez	2539123
UniProt	P07527
Other data
EC number	2.7.11.1

Wee1 is a nuclear kinase belonging to the Ser/Thr family of protein kinases in the fission yeast Schizosaccharomyces pombe (S. pombe). It has a molecular mass of 96 kDa and it is a key regulator of cell cycle progression. It influences cell size by inhibiting the entry into mitosis, through inhibiting Cdk1. It has homologues in many other organisms, including mammals.

The regulation of cell size is critical to ensure functionality of a cell. Besides environmental factors such as nutrients, growth factors and functional load, cell size is also controlled by a cellular cell size checkpoint.

Wee1 is a component of this checkpoint. It is a kinase determining the timepoint of entry into mitosis, thus influencing the size of the daughter cells. Loss of Wee1 function will produce smaller than normal daughter cell, because cell division occurs prematurely.

Its name is derived from the Scottish dialect word wee, meaning small - its discoverer Paul Nurse was working at the University of Edinburgh in Scotland at the time of discovery.

Wee1 inhibits Cdk1 by phosphorylating it on two different sites, Tyr15 and Thr14. Cdk1 is crucial for the cyclin-dependent passage of the various cell cycle checkpoints. At least three checkpoints exist for which the inhibition of Cdk1 by Wee1 is important:

Epigenetic function of Wee1 kinase has also been reported. Wee1 was shown to phosphorylate histone H2B at tyrosine 37 residue which regulated global expression of histones.

The WEE1 gene has two known homologues in humans, WEE1 (also known as WEE1A) and WEE2 (WEE1B). The corresponding proteins are Wee1-like protein kinase and Wee1-like protein kinase 2 which act on the human Cdk1 homologue Cdk1.