SPAG1, Official Symbol SPAG1provided by HGNC Official Full Name sperm associated antigen 1provided by HGNC Primary source HGNC:HGNC:11212 See related Ensembl:ENSG00000104450 MIM:603395; AllianceGenome:HGNC:11212 Gene type protein coding RefSeq status REVIEWED Organism Homo sapiens Lineage Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo Also known as SP75; TPIS; CT140; CILD28; DNAAF13; HSD-3.8; HEL-S-268 Summary The correlation of anti-sperm antibodies with cases of unexplained infertility implicates a role for these antibodies in blocking fertilization. Improved diagnosis and treatment of immunologic infertility, as well as identification of proteins for targeted contraception, are dependent on the identification and characterization of relevant sperm antigens. The protein expressed by this gene is recognized by anti-sperm agglutinating antibodies from an infertile woman. Furthermore, immunization of female rats with the recombinant human protein reduced fertility. This protein localizes to the plasma membrane of germ cells in the testis and to the post-acrosomal plasma membrane of mature spermatozoa. Recombinant polypeptide binds GTP and exhibits GTPase activity. Thus, this protein may regulate GTP signal transduction pathways involved in spermatogenesis and fertilization. Two transcript variants of this gene encode the same protein. [provided by RefSeq, Jul 2008] Expression Broad expression in colon (RPKM 8.4), testis (RPKM 7.5) and 22 other tissues See more Orthologs mouse all