MAP3K4
MAP3K4, also called MEKK4/MTK1, encodes a MAP kinase kinase kinase that links environmental stress to p38 MAPK and JNK signaling while sparing the ERK pathway[1]. Compared with related MEKK1/2/3 kinases, early cloning work distinguished MEKK4 by selective stress-pathway activation and absence of ERK activation[2]. Mechanistically, GADD45α/β/γ bind the MTK1 N-terminal domain and activate MTK1/MEKK4 kinase activity, connecting DNA-damage and environmental stress signals to p38/JNK activation[3][4]. In developmental models, MAP3K4 supports epithelial state control because MAP3K4/CBP-regulated H2B acetylation maintains trophoblast stem cell epithelial identity and restrains EMT[5]. Loss of MAP3K4 activity elevates HDAC6, weakens tight-junction gene regulation, and drives trophoblast stem cells toward epithelial-to-mesenchymal transition[6]. MAP3K4 kinase inactivation also causes fetal growth restriction through placental insufficiency and reduced IGF1R/IR-Akt signaling[7]. In disease models, MAP3K4 deficiency promotes invasive growth and EMT in intrahepatic cholangiocarcinoma, making MAP3K4 a practical target for studying stress signaling, EMT, placental development, and cancer invasion[8]. For experimental design, published studies support kinase-inactive MAP3K4 models, GADD45-mediated activation systems, and HDAC6 knockdown approaches rather than validated MAP3K4-specific agonists or inhibitors[3][4][6].
References:
- [1]. Takekawa M, et al. A human homolog of the yeast Ssk2/Ssk22 MAP kinase kinase kinases, MTK1, mediates stress-induced activation of the p38 and JNK pathways. EMBO J. 1997 Aug 15;16(16):4973-82. [Content Brief]
- [2]. Gerwins P, et al. Cloning of a novel mitogen-activated protein kinase kinase kinase, MEKK4, that selectively regulates the c-Jun amino terminal kinase pathway. J Biol Chem. 1997 Mar 28;272(13):8288-95. [Content Brief]
- [3]. Takekawa M, et al. A family of stress-inducible GADD45-like proteins mediate activation of the stress-responsive MTK1/MEKK4 MAPKKK. Cell. 1998 Nov 13;95(4):521-30. [Content Brief]
- [4]. Mita H, et al. Regulation of MTK1/MEKK4 kinase activity by its N-terminal autoinhibitory domain and GADD45 binding. Mol Cell Biol. 2002 Jul;22(13):4544-55. [Content Brief]
- [5]. Abell AN, et al. MAP3K4/CBP-regulated H2B acetylation controls epithelial-mesenchymal transition in trophoblast stem cells. Cell Stem Cell. 2011 May 6;8(5):525-37. [Content Brief]
- [6]. Mobley RJ, et al. MAP3K4 Controls the Chromatin Modifier HDAC6 during Trophoblast Stem Cell Epithelial-to-Mesenchymal Transition. Cell Rep. 2017 Mar 7;18(10):2387-2400. [Content Brief]
- [7]. Perry CH, et al. MAP3K4 promotes fetal and placental growth by controlling the receptor tyrosine kinases IGF1R/IR and Akt signaling pathway. J Biol Chem. 2022 Sep;298(9):102310. [Content Brief]
- [8]. Yang LX, et al. Mitogen-activated protein kinase kinase kinase 4 deficiency in intrahepatic cholangiocarcinoma leads to invasive growth and epithelial-mesenchymal transition. Hepatology. 2015 Dec;62(6):1804-16. [Content Brief]
