Encoded on the minus strand. 12 exons, exon number 1 is not depicted in the diagram and appears to undergo differential splicing, according to recent NCBI-AceView (accessed 17 Apr 2011).

Work by the Wurthner lab in 2003-2005 identified an 860 aa protein that could be matched with genomic sequences. Recently predicted proteins from mRNA variants describe translation products of 896, 952, 161 and 30 aminino acids (NCBI AceView, accessed 17 April 2011).

A fragment of TGFBRAP1 was initially identified in a Yeast-2-Hybrid screen as a TGF-beta type I receptor interacting protein (Charng et al., 2002). Further work by Wurthner et al. demonstrated binding of the full-length molecule exclusively to either TGF-beta receptor I and TGF-beta receptor II, or to Smad4, suggesting TGFBRAP1 to be a Smad4 chaperone (Wurthner et al., 2001). Furthermore, receptor activated Smads were shown to compete for binding of TRAP1 with Smad4, suggesting only a transient association between TRAP1 and Smad4. In addition, an interaction of TRAP1 with 5-lipoxgenase in a yeast two-hybrid system was described by a different group (Provost et al., 1999). Gene inactivation of TGFBRAP1 through conventional targeting leads to early developmental arrest of murine embryos around day E 6.5 (Messler et al., 2010).

Ubiquitous.

Punctate pattern suggestive of endosomal localisation.

Chaperone for Smad4 in the TGF-beta signal transduction cascade (Wurthner et al., 2001).
Endosomal trafficking (circumstantial evidence: domain structure and early embryonic lethality; Messler et al., 2010).

hVPS39 (hVam6, hTrap-like-Protein).