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Protein synthesis and secretion in the human epididymis and immunoreactivity with sperm antibodies
Author(s) -
Ross Peter,
Kan Frederick W. K.,
Antaki Pierre,
Vigneault Normand,
Chapdelaine Alcide,
Roberts Kenneth D.
Publication year - 1990
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080260104
Subject(s) - epididymis , sperm , biology , secretory protein , western blot , secretion , antibody , immunoprecipitation , immunofluorescence , membrane protein , capacitation , microbiology and biotechnology , blot , andrology , medicine , endocrinology , biochemistry , immunology , gene , membrane , genetics
Abstract The synthesis and secretion of proteins in the different regions of the human epididymis were studied in vitro. Epididymal tissues obtained from patients undergoing castration for prostatic carcinoma or from cadavers were incubated in the presence of [ 35 S]methionine, and the resulting radiolabeled proteins were analysed on SDS‐PAGE. The corpus region was found to be the most active segment in total protein synthesis. Significant qualitative and quantitative changes were observed in the pattern of proteins secreted from the different epididymal regions. To establish those epididymal proteins that interact with maturing sperm, the secreted products were immunoreacted with antibodies raised against a Triton X‐100 extract of ejaculated human sperm heads. The antibodies react mainly with the head region of ejaculated spermatozoa as judged by indirect immunofluorescence. Protein A‐gold labeling of freeze‐fracture images showed gold particle distribution on the sperm plasma membrane. Western blot analysis of the secreted proteins revealed four bands (66, 37, 32, and 29 kDa) in the proximal regions and six additional bands 80, 76, 48, 27, 22, and 17 (kDa) in the distal part of the epididymis. Immunoprecipitation of the secreted proteins with these antibodies revealed six radioactive bands of 170, 80, 76, 60, 48, and 37 kDa, which indicates that certain proteins of epididymal origin bind to the sperm plasma membrane.