Characterization of mouse Trip6: a putative intracellular signaling protein

Trip6 is a human LIM domain-containing protein that has been identified in yeast two-hybrid screens as interacting with a variety of proteins. Trip6 has been proposed to transport signals from the cell surface to the nucleus. In this report, we have characterized a mouse cDNA encoding Trip6. Mouse Trip6 is highly similar to human Trip6, especially in the C-terminal LIM domain region, and the in vitro and in vivo mouse Trip6 cDNA directs the synthesis of a polypeptide with a relative mobility of approx. 57 kDa on SDS-polyacrylomide gels. Full-length Trip6 localizes to discrete cytoplasmic patches when overexpressed in chicken embryo fibroblasts, consistent with localization to focal adhesion plaques. However, deletion of the N-terminal 115 amino acids allows Trip6 to enter the nucleus of CEF. A GAL4 fusion protein containing the LIM domain region of mouse Trip6 can activate transcription in yeast and chicken fibroblasts. Our results indicate that the functional domains and properties of mouse Trip6 are highly conserved between humans and mice, and are consistent with a model in which Trip6 relays signals from the cell surface to the nucleus.