Molecular cloning of a cDNA encoding a novel small GTP-binding protein

A cDNA encoding a small GTP-binding protein, S10, was cloned from Jurkat cells. The deduced amino acid sequence of S10 had the structural features characteristic to this family of proteins with highest homology to rab subfamily. Northern blot analysis revealed that this gene is expressed only in lymphoid cell lines and a histiocytic leukemia, U937. Hence, it should have a specialized function in cells derived from the hematopoietic stem cell.