GTP-binding proteins of the Rab family were cloned from human platelets using RT-PCR. Clones corresponding to twonovelRabproteins,Rab31 andRab32, and toRab11A, which had not been detected in platelets previously, were isolated. The coding sequence of Rab31(GenBank acces-sion no. U59877) corresponded to a 194 amino-acid protein of kDa. TheRab32sequence was extended to 1000 nucleotides including 630 nucleotides of coding sequence (GenBank accession no.