Predominantly expressed in thymus, spleen, and testis. Expressed at lower levels in brain, heart, lung, kidney, and skeletal muscle. In testis, specifically expressed in spermatocytes and round spermatids. Up-regulated in thioglycolate-elicited mouse peritoneal macrophages. Belongs to the TRAFAC class translation factor GTPase superfamily. Classic translation factor GTPase family. GTPBP1 subfamily.