Beta-microseminoprotein is a protein that in humans is encoded by the MSMBgene.[5][6] For historical reasons, the scientific literature may also refer to this protein as Prostate secretory protein 94 (PSP94), microseminoprotein (MSP), microseminoprotein-beta (MSMB), beta-inhibitin, prostatic inhibin peptide (PIP), and inhibitin like material (ILM).
MSMB is one of the three major proteins secreted by the epithelial cells of the prostate[7] and has a concentration in seminal plasma of 0.5 to 1 mg/mL[8] Two comprehensive studies of beta-microseminoprotein in tissue have shown that it is secreted by epithelial cells in many other organs: liver, lung, breast, kidney, colon, stomach, pancreas, esophagus, duodenum, salivary glands, fallopian tube, corpus uteri, bulbourethral glands and cervix.[9][10] This list corresponds closely to the sites from which all late onset cancers develop.[11]
MSMB is a rapidly evolving protein.[12] Solution structures of human and porcine MSMB show remarkable similarity despite having only 51% of amino acids in common.[13] The C-terminus domain of MSMB contains two two-stranded β-sheets; these have no resemblance to other structural motifs.[13] The rapid evolution of MSMB can be attributed to either sexual selection or innate pathogen defense;[14] the wide distribution of MSMB in the body and the fungicidal properties of the C-terminus suggest that innate pathogen defense plays a role in driving this evolution.[15]
Beta-microseminoprotein is a member of the immunoglobulin binding factor family. This protein has been reported to have inhibin-like properties,[16] though this finding has been disputed.[17][18] It may have a role as an autocrine and/or paracrine factor in uterine, breast, and other female reproductive tissues.[citation needed] Two alternatively spliced transcript variants encoding different isoforms are described for this gene. Despite having only 4 out of 11 amino acids in common, both the porcine and human fungicidal peptide on MSMB's C-terminus are potently fungicidal in the absence of calcium ions.[15] The protein inhibits growth of cancer cells in an experimental model of prostate cancer,[19][20] though this property is cell line–specific.[21]
Two large genome-wide association studies showed that decreased expression of the MSMB protein caused by the rs10993994 single nucleotide polymorphism is associated with an increased risk of developing prostate cancer (odds ratio for CT allele pair ~1.2x, and for TT allele pair ~1.6x, when compared to the low risk CC allele pair).[22] A 2003 study proposed using a truncated form of the MSMB protein called PSP61 as a biomarker for benign prostatic hyperplasia (BPH). This study found PSP61 in the expressed prostatic secretion of 10 out of 10 men suffering from BPH, while not finding it in 10 out of 10 age-matched BPH-free men.[23] This truncated form of the MSMB protein lacks the fungicidal peptide identified in 2012. The expression of MSMB is found to be decreased in prostate cancer, so it may be usable as a biomarker for prostate cancer.[24] Urinary MSMB has been found to be superior to urinary PSA at differentiating men with prostate cancer, at all Gleason grades.[25]
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Ulvsback M, Spurr NK, Lundwall A (Mar 1992). "Assignment of the human gene for beta-microseminoprotein (MSMB) to chromosome 10 and demonstration of related genes in other vertebrates". Genomics. 11 (4): 920–4. doi:10.1016/0888-7543(91)90015-7. PMID1783399.
^Ohkubo I, Tada T, Ochiai Y, Ueyama H, Eimoto T, Sasaki M (June 1995). "Human seminal plasma beta-microseminoprotein: its purification, characterization, and immunohistochemical localization". Int. J. Biochem. Cell Biol. 27 (6): 603–11. doi:10.1016/1357-2725(95)00021-G. PMID7671139.
^Laurence M (2018). PSP94, what is it good for? Sixth edition.
^Nolet S, St-Louis D, Mbikay M, Chrétien M (April 1991). "Rapid evolution of prostatic protein PSP94 suggested by sequence divergence between rhesus monkey and human cDNAs". Genomics. 9 (4): 775–7. doi:10.1016/0888-7543(91)90375-o. PMID2037304.
^ abGhasriani H, Teilum K, Johnsson Y, Fernlund P, Drakenberg T (September 2006). "Solution structures of human and porcine beta-microseminoprotein". J. Mol. Biol. 362 (3): 502–15. doi:10.1016/j.jmb.2006.07.029. PMID16930619.
^Kohan S, Fröysa B, Cederlund E, Fairwell T, Lerner R, Johansson J, Khan S, Ritzen M, Jörnvall H, Cekan S (April 1986). "Peptides of postulated inhibin activity. Lack of in vitro inhibin activity of a 94-residue peptide isolated from human seminal plasma, and of a synthetic replicate of its C-terminal 28-residue segment". FEBS Lett. 199 (2): 242–8. doi:10.1016/0014-5793(86)80488-4. PMID3084296. S2CID33940801.
^Garde S, Sheth A, Porter AT, Pienta KJ (1993). "Effect of prostatic inhibin peptide (PIP) on prostate cancer cell growth in vitro and in vivo". Prostate. 22 (3): 225–33. doi:10.1002/pros.2990220305. PMID8488155. S2CID20872869.
^Shukeir N, Arakelian A, Kadhim S, Garde S, Rabbani SA (May 2003). "Prostate secretory protein PSP-94 decreases tumor growth and hypercalcemia of malignancy in a syngenic in vivo model of prostate cancer". Cancer Res. 63 (9): 2072–8. PMID12727822.
^Eeles RA, Kote-Jarai Z, Giles GG, Olama AA, Guy M, Jugurnauth SK, Mulholland S, Leongamornlert DA, Edwards SM, Morrison J, et al. (March 2008). "Multiple newly identified loci associated with prostate cancer susceptibility". Nat. Genet. 40 (3): 316–21. doi:10.1038/ng.90. PMID18264097. S2CID30968525.
^Xu K, Wang X, Ling MT, Lee DT, Fan T, Chan FL, Xuan JJ, Tsao SW, Wong YC (April 2003). "Identification of a specifically expressed modified form of novel PSP-94 protein in the secretion of benign prostatic hyperplasia". Electrophoresis. 24 (7–8): 1311–8. doi:10.1002/elps.200390167. PMID12707925. S2CID21348603.
^Whitaker HC, Warren AY, Eeles R, Kote-Jarai Z, Neal DE (February 2010). "The potential value of microseminoprotein-beta as a prostate cancer biomarker and therapeutic target". Prostate. 70 (3): 333–40. doi:10.1002/pros.21059. PMID19790236. S2CID206397505.
Liang ZG, Kamada M, Koide SS (1991). "Structural identity of immunoglobulin binding factor and prostatic secretory protein of human seminal plasma". Biochem. Biophys. Res. Commun. 180 (1): 356–9. doi:10.1016/S0006-291X(05)81300-2. PMID1930232.
Nolet S, Mbikay M, Chrétien M (1991). "Prostatic secretory protein PSP94: gene organization and promoter sequence in rhesus monkey and human". Biochim. Biophys. Acta. 1089 (2): 247–9. doi:10.1016/0167-4781(91)90016-F. PMID2054385.
Green CB, Liu WY, Kwok SC (1990). "Cloning and nucleotide sequence analysis of the human beta-microseminoprotein gene". Biochem. Biophys. Res. Commun. 167 (3): 1184–90. doi:10.1016/0006-291X(90)90648-7. PMID2322265.
Ito Y, Tsuda R, Kimura H (1989). "Ultrastructural localizations of beta-microseminoprotein, a prostate-specific antigen, in human prostate and sperm: comparison with gamma-seminoprotein, another prostate-specific antigen". J. Lab. Clin. Med. 114 (3): 272–7. PMID2475560.
Ulvsbäck M, Lindström C, Weiber H, et al. (1989). "Molecular cloning of a small prostate protein, known as beta-microsemenoprotein, PSP94 or beta-inhibin, and demonstration of transcripts in non-genital tissues". Biochem. Biophys. Res. Commun. 164 (3): 1310–5. doi:10.1016/0006-291X(89)91812-3. PMID2590204.
Mbikay M, Nolet S, Fournier S, et al. (1987). "Molecular cloning and sequence of the cDNA for a 94-amino-acid seminal plasma protein secreted by the human prostate". DNA. 6 (1): 23–9. doi:10.1089/dna.1987.6.23. PMID3829888.
Akiyama K, Yoshioka Y, Schmid K, et al. (1985). "The amino acid sequence of human beta-microseminoprotein". Biochim. Biophys. Acta. 829 (2): 288–94. doi:10.1016/0167-4838(85)90200-6. PMID3995056.
Liu AY, Bradner RC, Vessella RL (1994). "Decreased expression of prostatic secretory protein PSP94 in prostate cancer". Cancer Lett. 74 (1–2): 91–9. doi:10.1016/0304-3835(93)90049-F. PMID7506990.
Xuan JW, Chin JL, Guo Y, et al. (1995). "Alternative splicing of PSP94 (prostatic secretory protein of 94 amino acids) mRNA in prostate tissue". Oncogene. 11 (6): 1041–7. PMID7566962.
Ochiai Y, Inazawa J, Ueyama H, Ohkubo I (1995). "Human gene for beta-microseminoprotein: its promoter structure and chromosomal localization". J. Biochem. 117 (2): 346–52. doi:10.1093/jb/117.2.346. PMID7608123.
Ohkubo I, Tada T, Ochiai Y, et al. (1995). "Human seminal plasma beta-microseminoprotein: its purification, characterization, and immunohistochemical localization". Int. J. Biochem. Cell Biol. 27 (6): 603–11. doi:10.1016/1357-2725(95)00021-G. PMID7671139.
Fernlund P, Granberg LB, Roepstorff P (1994). "Amino acid sequence of beta-microseminoprotein from porcine seminal plasma". Arch. Biochem. Biophys. 309 (1): 70–6. doi:10.1006/abbi.1994.1086. PMID8117114.
Sasaki T, Matsumoto N, Jinno Y, et al. (1997). "Assignment of the human beta-microseminoprotein gene (MSMB) to chromosome 10q11.2". Cytogenet. Cell Genet. 72 (2–3): 177–8. doi:10.1159/000134180. PMID8978767.
Kamada M, Mori H, Maeda N, et al. (1998). "beta-Microseminoprotein/prostatic secretory protein is a member of immunoglobulin binding factor family". Biochim. Biophys. Acta. 1388 (1): 101–10. doi:10.1016/S0167-4838(98)00164-2. PMID9774712.
