Overview:

HGK is the mitogen-activated protein kinase kinase kinase kinase 4(MAP4K4) and a member of the serine/threonine protein kinase family. HGK has been shown to specifically activate MAPK8/JNK (1). The activation of MAPK8 by HGK can be inhibited by dominant-negative mutants of MAP3K7/TAK1, MAP2K4/MKK4, and MAP2K7/MKK7, which suggest that this kinase functions through the MAP3K7-MAP2K4-MAP2K7 kinase cascade and mediates TNF-α signaling. HGK-dependent signaling inhibits PPARγ-responsive gene expression, adipogenesis, and insulin-stimulated glucose transport (2).

Gene Aliases:

MAP4K4, NIK, FLH21957, FLJ10410, FLJ20373, FLJ90111, KIAA0687

Genbank Number:

NP_004825

References:

1. Yao, Z. et.al: A novel human STE20-related protein kinase, HGK, that specifically activates the c-jun N-terminal kinase signaling pathway. J. Biol. Chem. 274: 2118-2125, 1999.

2. Tang, X. et.al: An RNA interference-based screen identifies MAP4K4/NIK as a negative regulator of PPAR-gamma, adipogenesis, and insulin-responsive hexose transport. Proc. Nat. Acad. Sci. 103: 2087-2092, 2006.