Kinase Group STE

This group consists of three related families which sequentially activate each other to then activate the MAPK family. The Ste7 family directly phosphorylate MAPKs, and are also known as MAP2K, MEK, or MKKs; Ste11 members phosphorylate Ste7 kinases and are called MAP3K, while many Ste20 members (MAP4K) act on Ste11 kinases. Naming is based on the members of the canonical MAPK cascade in yeast.

MAP3K activity is also found in members of the TKL group, in kinases such as Raf and MLK, as well as in the 'Other' kinase, MOS.

Ste7 and Ste11 families are not currently subdivided, though preliminary evidence from the urchin genome shows that several subfamilies are found throughout deuterostomes and correlate with functional information. The Ste20 family is the largest of the three and is divided into many subfamilies. Some are implicated in MAPK cascades, while others are not and may have completely distinct functions.