Open AccessStructure and function of epididymal protein cysteine‐rich secretory protein‐1
Author(s) -
Roberts Kenneth P.,
Johnston Daniel S.,
Nolan Michael A.,
Wooters Joseph L.,
Waxmonsky Nicole C.,
Piehl Laura B.,
EnsrudBowlin Kathy M.,
Hamilton David W.
Publication year - 2007
Publication title -
asian journal of andrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.701
H-Index - 74
eISSN - 1745-7262
pISSN - 1008-682X
DOI - 10.1111/j.1745-7262.2007.00318.x
Subject(s) - capacitation , sperm , epididymis , cysteine , microbiology and biotechnology , biology , population , secretory protein , function (biology) , glycoprotein , proteomics , biochemistry , genetics , secretion , gene , demography , sociology , enzyme
Cysteine‐rich secretory protein‐1 (CRISP‐1) is a glycoprotein secreted by the epididymal epithelium. It is a member of a large family of proteins characterized by two conserved domains and a set of 16 conserved cysteine residues. In mammals, CRISP‐1 inhibits sperm‐egg fusion and can suppress sperm capacitation. The molecular mechanism of action of the mammalian CRISP proteins remains unknown, but certain non‐mammalian CRISP proteins can block ion channels. In the rat, CRISP‐1 comprises two forms referred to as Proteins D and E. Recent work in our laboratory demonstrates that the D form of CRISP‐1 associates transiently with the sperm surface, whereas the E form binds tightly. When the spermatozoa are washed, the E form of CRISP‐1 persists on the sperm surface after all D form has dissociated. Cross‐linking studies demonstrate different protein‐protein interaction patterns for D and E, although no binding partners for either protein have yet been identified. Mass spectrometric analyses revealed a potential post‐translational modification on the E form that is not present on the D form. This is the only discernable difference between Proteins D and E, and presumably is responsible for the difference in behavior of these two forms of rat CRISP‐1. These studies demonstrate that the more abundant D form interacts with spermatozoa transiently, possibly with a specific receptor on the sperm surface, consistent with a capacitation‐suppressing function during sperm transit and storage in the epididymis, and also confirm a tightly bound population of the E form that could act in the female reproductive tract.