Premium
Role of TAK1 and TAB1 in BMP signaling in early Xenopus development
Author(s) -
Shibuya Hiroshi,
Iwata Hiroshi,
Masuyama Norihisa,
Gotoh Yukiko,
Yamaguchi Kyoko,
Irie Kenji,
Matsumoto Kunihiro,
Nishida Eisuke,
Ueno Naoto
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.4.1019
Subject(s) - biology , xenopus , microbiology and biotechnology , signal transduction , smad2 protein , smad , genetics , gene
Transforming growth factor‐β (TGF‐β) superfamily members elicit signals through stimulation of serine/threonine kinase receptors. Recent studies of this signaling pathway have identified two types of novel mediating molecules, the Smads and TGF‐β activated kinase 1 (TAK1). Smads were shown to mimic the effects of bone morphogenetic protein (BMP), activin and TGF‐β. TAK1 and TAB1 were identified as a MAPKKK and its activator, respectively, which might be involved in the up‐regulation of TGF‐β superfamily‐induced gene expression, but their biological role is poorly understood. Here, we have examined the role of TAK1 and TAB1 in the dorsoventral patterning of early Xenopus embryos. Ectopic expression of Xenopus TAK1 (xTAK1) in early embryos induced cell death. Interestingly, however, concomitant overexpression of bcl‐2 with the activated form of xTAK1 or both xTAK1 and xTAB1 in dorsal blastomeres not only rescued the cells but also caused the ventralization of the embryos. In addition, a kinase‐negative form of xTAK1 (xTAK1KN) which is known to inhibit endogenous signaling could partially rescue phenotypes generated by the expression of a constitutively active BMP‐2/4 type IA receptor (BMPR‐IA). Moreover, xTAK1KN could block the expression of ventral mesoderm marker genes induced by Smad1 or 5. These results thus suggest that xTAK1 and xTAB1 function in the BMP signal transduction pathway in Xenopus embryos in a cooperative manner.