Overview:

MEK5, which is also known as MKK5, is a dual specificity serine/threonine protein kinase that belongs to the MAP kinase kinase family. MEK5 specifically activates ERK5 (1) and MEK5 itself is regulated by MEKK3 (2). Phosphorylation of MEK5 at Ser311 and Thr315 has been implicated in cell proliferation (3). Indeed, there is an important link between MEK5 and metastatic prostate cancer (4).

References:

1. Zhou G et al: Components of a new human protein kinase signal transduction pathway. J. Biol. Chem. 1995 270(21):12665-9. 2. Chao T H, et al: MEKK3 directly regulates MEK5 activity as part of the big mitogen-activated protein kinase 1 (BMK1) signaling pathway. J. Biol. Chem. 1999 274(51):36035-8. 3. Cameron S J. et al: Differential role of MEK5alpha and MEK5beta in BMK1/ERK5 activation. J. Biol. Chem. 2004 279(2):1506-12.4. Mehta P B, et al: MEK5 overexpression is associated with metastatic prostate cancer, and stimulates proliferation, MMP-9 expression and invasion. Oncogene 2003 22(9):1381-9.