MAPK4
Description
The MAPK4 (mitogen-activated protein kinase 4) is a protein-coding gene located on chromosome 18.
MAPK4 is an enzyme encoded by the MAPK4 gene in humans. It is a member of the mitogen-activated protein kinase family. Tyrosine kinase growth factor receptors activate MAPK4, which then translocates to the nucleus and phosphorylates nuclear targets. In Arabidopsis, MAPK4 plays a role in signaling. MAPK4 directly activates AKT by phosphorylating it at threonine 308, and also activates mTORC2 to phosphorylate AKT at serine 473, fully activating it. Overexpression of MAPK4 leads to oncogenic effects, such as transforming prostate epithelial cells to grow independently of anchorage. Conversely, suppressing MAPK4 inhibits cancer cell proliferation, anchorage-independent growth, and xenograft growth.
MAPK4 is an atypical MAPK protein that phosphorylates microtubule-associated protein 2 (MAP2) and MAPKAPK5. The exact function of the complex formed with MAPKAPK5 is unknown, but it involves a complex series of phosphorylation events. Upon interaction with MAPKAPK5, MAPK4 is phosphorylated at Ser-186 and then activates MAPKAPK5 by phosphorylation, which in turn phosphorylates MAPK4. This interaction may promote cell cycle entry.
MAPK4 is also known as ERK-4, ERK4, PRKM4, p63-MAPK, p63MAPK.
