title: Identification, purification and characterization of a novel human blood protein with binding affinity for prostate secretory protein of 94 amino acids.
abstract: PSP94 (prostate secretory protein of 94 amino acids), an abundant protein within semen, has reported local functions within the reproductive tract and reported systemic functions. Mechanisms of action remain poorly understood, but binding to undefined molecules within the prostate, pituitary, testis and blood may initiate some of these actions. PSP94 serum measurements, especially of bound and free forms, have potential clinical utility in prostate cancer management. Identification of the binding molecules will help in the understanding of PSP94's action, and enable further development of PSP94 serum assays. PSPBP (PSP94-binding protein) was purified from human serum by ammonium sulphate fractionation, ion-exchange and affinity chromatography. The glycosylated protein ran as two bands on SDS/PAGE (70 and 95 kDa). N-terminal sequencing yielded a 30-amino-acid sequence, identical with the translated N-terminal region of a previously published cDNA (GenBank accession number AX136261). Reverse transcriptase PCR and plaque hybridization demonstrated PSPBP mRNA in peripheral blood leucocytes and in a prostate cDNA library. Northern blotting showed 2 kb mRNA species in prostate, testis, ovary and intestine. Immunohistochemistry demonstrated PSPBP in tissues, including pituitary and Leydig cells, supporting a role for PSP94 in hormonal control at the pituitary gonadal axis. ELISA demonstrated that PSPBP levels were significantly lower (P=0.0014) in the serum of a prostate cancer population (n=65) compared with a control population (n=70). PSPBP identification will help the understanding of PSP94's functions and facilitate ELISA development to address the clinical value of PSP94 serum assays.
authors.affiliation: Procyon Biopharma Inc., 1650 TransCanada, Suite 200, Dorval, Québec, Canada H9P 1H7. jreeves@procyonbiopharma.com
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Reeves
authors.forename: Jim W
authors.initials: JW
authors.lastname: Xuan
authors.forename: Katerina
authors.initials: K
authors.lastname: Arfanis
authors.forename: Catherine
authors.initials: C
authors.lastname: Morin
authors.forename: Seema V
authors.initials: SV
authors.lastname: Garde
authors.forename: Marcia T
authors.initials: MT
authors.lastname: Ruiz
authors.forename: Jan
authors.initials: J
authors.lastname: Wisniewski
authors.forename: Chandra
authors.initials: C
authors.lastname: Panchal
authors.forename: Jerome E
authors.initials: JE
authors.lastname: Tanner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000595:Amino Acid Sequence; D000596:Amino Acids; D000911:Antibodies, Monoclonal / Q000276:immunology; D001798:Blood Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D015153:Blotting, Western; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D003001:Cloning, Molecular; D020869:Gene Expression Profiling; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011467:Prostate / Q000378:metabolism / Q000473:pathology; D011471:Prostatic Neoplasms / Q000097:blood; D029584:Prostatic Secretory Proteins / Q000378:metabolism*; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D000596:Amino Acids; D000911:Antibodies, Monoclonal; D001798:Blood Proteins; D002352:Carrier Proteins; D006023:Glycoproteins; C501293:PI16 protein, human; D029584:Prostatic Secretory Proteins; D012333:RNA, Messenger; C043076:beta-microseminoprotein