Molecular characterization of two novel isoforms and a soluble form of mouse CLEC-2.

CLEC-2 was first identified by sequence similarity to C-type lectin-like molecules with immune functions. Recently, human CLEC-2 has been reported as a receptor for the platelet-aggregating snake venom toxin rhodocytin and the endogenous sialoglycoprotein podoplanin. It has also been reported to facilitate the capture of HIV-1. However, investigation of mouse CLEC-2 (mCLEC-2) has little progressed after its identification. In this study, we identified two novel splicing variants of mCLEC-2 derived from omission of exon 2 and 2/4, respectively. These two variants had different expression profiles and subcellular localization from full-length mCLEC-2. Moreover, we observed that full-length mCLEC-2 could be cleaved probably by proteases sensitive to aprotinin and PMSF into a soluble form that partially existed as a disulfide-linked homodimer. The results presented here represent a further advancement toward the understanding of mCLEC-2.