Molecular cloning and characterization of a cDNA encoding the human leucocyte vacuolar protein sorting (h1Vps45)

We have isolated a novel cDNA clone from human leucocyte cDNA library, encoding a Sec1p-like vacuolar protein sorting (h1Vps45) which is believed to be implicated in vesicular transportation. Although the deduced amino acid (AA) sequence of this cDNA has revealed 97% identity to other known mammalian vacuolar protein sorting, there is an extensive variation in nucleotide sequence in comparison to that of three previously reported human (hVps45), rat (rVps45) and mouse (mVps45) vacuolar protein sorting (Vps45) cDNAs [1-3]. At the nucleotide sequence level h1Vps45 demonstrated 90% homology to the hVps45 and rVps45 and 89% identity to mVps45 with no significant homology in their noncoding regions. The 2.4 Kb mRNA corresponding to the h1Vps45 clone is widely distributed in a variety of human tissues expressing highest levels in peripheral blood mononuclear cells (PBMC), neutrophils, heart, spleen, and testis. The chromosomal mapping studies have demonstrated that the h1Vps45 is localized to long arm of human chromosome 1 at q21-q22. Our data indicates that we have isolated, characterized and mapped a novel cDNA encoding h1Vps45, which may play an important role in protein trafficking as well as have clinical significance in the release of inflammatory mediators e.g. histamine, bradykinin and cytokine release.