Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sperm capacitation is a maturation step that is deemed to be essential for sperm to fertilize an oocyte. A family of proteins, the binder of sperm (BSP), are known to bind choline phospholipids on sperm membranes and promote capacitation in bulls and boars. Recently, BSP-homologous genes have been identified in the epididymal tissues of human (BSPH1) and mouse (Bsph1, Bsph2). The aim of this study was to determine the binding characteristics of the murine binder of sperm protein homolog 1 (BSPH1) and evaluate its effects on sperm capacitation. Since it is not possible to purify the native BSP proteins from human and mouse in sufficient quantity, a murine recombinant BSPH1 (rec-BSPH1) was produced and used for the functional studies. Similarly to BSP proteins from other species, rec-BSPH1 bound to gelatin, heparin, phosphatidylcholine liposomes, and sperm. Both native BSPH1 and rec-BSPH1 were detected on the head and the midpiece region of sperm, although a stronger signal was detected on the midpiece region when sperm were incubated in a capacitating media containing bovine serum albumin. More importantly, murine rec-BSPH1 was able to capacitate sperm, but was unable to induce the acrosome reaction. These results show that murine epididymal BSPH1 shares many biochemical and functional characteristics with BSP proteins secreted by seminal vesicles of ungulates, and suggest that it might play a similar role in sperm functions.
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PMID:Characterization of recombinant murine binder of sperm protein homolog 1 and its role in capacitation. 2253 76

Proteins of the Binder of SPerm superfamily are known to bind choline phospholipids on sperm membrane and promote sperm capacitation. The current study focuses on the biochemical and functional characterization of the murine Binder of SPerm homolog 2 (BSPH2). A recombinant protein (rec-BSPH2) was expressed in Escherichia coli Rosetta-gami B (DE3)pLysS cells using pET32a vector. It was purified by immobilized metal ion affinity chromatography and refolded on column using a decreasing urea gradient. Rec-BSPH2 was found to share some binding characteristics with other BSP proteins, such as binding to gelatin, heparin, and epididymal sperm. Rec-BSPH2 as well as murine recombinant BSPH1 were found to have different immunofluorescence patterns when bound to uncapacitated versus capacitated sperm, indicating a rearrangement of these proteins on sperm surface during or following capacitation. Surprisingly, rec-BSPH2 was unable to bind phosphorylcholine liposomes or promote sperm capacitation. It is the first time that such results are reported for proteins of the BSP family. The results indicate that murine BSPH1 and BSPH2 might not have redundant functions, as is the case with bovine BSPs. This study could lead to a better understanding of the role of BSP proteins in sperm functions and the existence of redundant BSP proteins in the reproductive tract.
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PMID:Murine Binder of SPerm homolog 2 (BSPH2): the black sheep of the BSP superfamily. 2430 7