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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The photoaffinity analog [32P]8-N3 cAMP (8-azido adenosine 3',5'-monophosphate was used to analyze the membrane sidedness of rat sperm cAMP binding proteins during epididymal maturation. Evidence is presented here which supports the hypothesis that 35-45% of the regulatory subunits of the Type I and Type II cAMP-dependent protein kinases are readily available to externally added cyclic nucleotide. It was observed by sodium dodecyl sulfate gel electrophoresis (SDS-PAGE) and autoradiography that only two rat sperm proteins (Mr = 49K and 55K) were photolabeled which comigrated on gels with partially purified Type I and Type II regulatory subunits, respectively. Both of these photolabeled epididymal sperm proteins were saturated at physiological titers of [32P]8-N3cAMP and photoincorporation of [32P]8-N3 cAMP was specific since other SDS-resolvable sperm proteins did not photoincorporate the analog. Caput and cauda sperm protein photoincorporation could be effectively blocked by low levels of cAMP, but not by cGMP, ATP or GTP. Sperm epididymal maturation coincided with changes in the cAMP-dependent protein kinase subunits since cauda sperm contained more available Type II than did caput sperm. A subcellular analysis of cAMP-dependent protein kinase regulatory subunit in head and tail fractions was done for caput and cauda sperm and demonstrated that the tail fractions showed more photo-labeling of both Type I and II regulatory subunits than did the head fractions.
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PMID:A study of rat epididymal sperm adenosine 3',5'-monophosphate-dependent protein kinases: maturation differences and cellular location. 298 32

An inactive form of acrosin was extracted from epididymal boar spermatozoa utilizing acid pH conditions. When subjected to activation in alkaline environment, this form turns into an enzymatically active species, which exhibits close-related electrophoretic characteristics. Both the precursor and the activated species, when incubated in the presence of thermolysin, give rise to two fastly moving acrosin molecular forms. In order to establish the nature of the true acrosin zymogen, we isolated poly(A+)-RNA from boar testicles, performed its translation in vitro in the presence of [35S]-methionine and reticulocyte lysate, immunoprecipitated the translation products with anti-boar acrosin antibody, and analyzed them by SDS-polyacrylamide gel electrophoresis and autoradiography. A single translation product of molecular weight 55,000 was detected. It is concluded that the polypeptide chain of the boar zymogen is of 55,000; increases in molecular weight are due to post-translational modifications, like glycosylation.
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PMID:Biochemical studies on proacrosin and acrosin from epididymal boar spermatozoa: in vitro translation of boar testicular proacrosin mRNA. 309 Oct 10

The proacrosin-acrosin proteinase system was measured and partially characterized in unpurified extracts of washed hamster epididymal sperm. Autoactivation experiments demonstrated that proacrosin accounted for greater than 98% of the acrosin activity in the sperm extracts from individual animals. Several bands of proteinase activity were observed on gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophoretic (gelatin-SDS-PAGE) zymography. The major proteinase activities in the nonactivated extracts corresponded to relative molecular masses (Mr) of 51,000 to 56,000, while less distinct digestion occurred with relative molecular masses of 37,000 to 49,000. It was demonstrated that after a serial dilution of the sperm extract, the proteinase activity in as few as 6,000 sperm could readily be detected by the gelatin-SDS-PAGE methods. Time-course activation studies showed that the zymogen was completely converted to active proteinase in 45-60 min at pH 8.0 and 25 degrees C. This autoconversion process was markedly inhibited by calcium, sodium, and heparin. However, each of these compounds stimulated the proteolytic activity of acrosin. These studies demonstrate that the proacrosin-acrosin system can be investigated in extracts of nonpurified hamster epididymal sperm.
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PMID:Quantification and partial characterization of the hamster sperm proacrosin-acrosin system. 309 98

Previous studies showed that interspecies differences in proacrosin size may exist. We purified guinea pig proacrosins, one from testes and two from epididymal spermatozoa, by gel filtration and cation exchange at acidic pH. Final purification was by cation exchange at pH 8.0 in 6 M urea. Testis proacrosin migrated with 62,000 Mr in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). One sperm proacrosin migrated with 43,000 Mr, and the other as a 56,000/54,000 Mr doublet in SDS-PAGE. These results represent the first purification of three forms of proacrosin from one species, and the first purification to homogeneity of a 43,000 Mr proacrosin. The proacrosins autoactivate at pH 8.0 with similar kinetics, copurify until the last purification step, and share antigenic determinants. It is possible that the sperm proacrosins are derived from the testis proacrosin, perhaps by proteolysis. The sizes of the three guinea pig proacrosins reported in this study are similar to those reported for proacrosins from other species. Apparent interspecies differences in proacrosin size may be primarily a question of which of at least three possible forms of the zymogen predominates in a species.
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PMID:Purification and initial characterization of proacrosins from guinea pig testes and epididymal spermatozoa. 311 22

The epididymis of the ram synthesizes under androgenic control of specific 64 kD protein. The purified protein appeared as a single band in SDS polyacrylamide gel electrophoresis. It was labelled and an antiserum was prepared in mice. Results showed localization of receptors sites for 64 kD on the periacrosomal plasma membrane of testicular spermatozoa. The protein itself was found on the periacrosomal area of both epididymal and ejaculated spermatozoa.
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PMID:[Localization, on the head of ram spermatozoa, of affinity sites for the 64kD androgen dependent epididymal prealbumin]. 313 11

We report in this paper that proteins from the surface of ejaculated spermatozoa contain antigenic determinants cross-reacting with a rabbit antiserum raised against native CFS, a protein secreted from the rat seminal vesicle and composed of two subunits, namely RSV IV and RSV V. Conversely, no such proteins could be extracted from cauda epididymal spermatozoa. The cross-reacting proteins derived from the ejaculated spermatozoa were analyzed by SDS-PAGE. An electrophoretic pattern different than that expected for native CFS in denaturing conditions was found. In vitro reconstitution experiments showed that labeled native CFS is able to bind cauda epididymal spermatozoa. The CFS protein recovered from the sperm surface was examined and alterations of its structure were also noted. The sperm-coating abilities of CFS and of its RSV IV subunit are discussed.
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PMID:Detection of sperm-coating antigens immunologically related to a seminal protein in rat. 324 84

Vasectomy was performed on inbred Lewis rats to induce anti-sperm autoantibodies and to identify their cognate autoantigens. Different detergent extracts of cauda epididymal spermatozoa were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), blotted to nitrocellulose, and probed with sera from pre-vasectomy, post-vasectomy, and hyperimmunized animals to detect isologous sperm antigens. Nonreduced SDS-soluble autoantigens at greater than 200, 86, 43, and 26 kDa were bound by post-vasectomy antisera. Reduction of SDS-soluble antigens resulted in increased staining of the 86, 72-63, and 43 kDa autoantigens. Laemmli extraction of SDS insoluble pellets with beta-mercaptoethanol generated the largest repertoire of autoantigens including several autoantigens found in SDS-soluble extracts. Therefore, to analyze the entire repertoire of post-vasectomy autoantigens, whole sperm were extracted with Laemmli buffer under reducing conditions. Autoantiserum from most vasectomized animals bound Laemmli-extracted reduced autoantigens of approximately 86 (89-78), 63, 43, and 20 (21-16) kDa. Testicular extracts, reduced and separated by SDS-PAGE, contained autoantigens of 76, 60, and 42 kDa that were also recognized by hyperimmune and post-vasectomy antisera. The repertoire of sperm antigens recognized by pooled serum from hyperimmunized animals was similar to the cumulative repertoire recognized by post-vasectomy sera. These studies define several major sperm autoimmunogens recognized by post-vasectomy antisera and indicate that many of these peptide autoimmunogens are disulfide-bonded complexes.
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PMID:Post-vasectomy sperm autoimmunogens in the Lewis rat. 326 39

We report here recent findings on the sperm maturation antigen SMA4, which is secreted by holocrine cells of the distal caput epididymis and binds to the flagellar surface of mouse sperm during epididymal transit. Washed sperm from the caput and corpus epididymides of mice were examined by immunofluorescence and SDS-PAGE using wheat germ agglutinin, which binds specifically to SMA4 as a primary probe. Results indicate that sperm first exhibit WGA reactivity on their flagellae in the region of the distal caput, and that the appearance of WGA receptors is due to the binding of a 54-Kd glycoprotein (SMA4) to the cell surface. Extracts of epididymis containing SMA4 were tested for their ability to bind to the surfaces of caput and corpus sperm. Caput sperm surfaces bound SMA4 in a temperature-independent manner, and binding occurred in the presence of enzyme inhibitors, suggesting a nonenzymatic process. Biochemical studies revealed that SMA4 contains disulfide bonds which stabilize it on the sperm surface and restrict its mobility. Terminal carbohydrate residues of the molecule are sialic acids. The addition of SMA4 to caput sperm flagellae prevented tail-to-tail agglutination, normally seen when caput sperm are diluted into saline; and SMA4 was able to disperse clumps of agglutinated caput sperm. The data suggest that a primary function of SMA4 is to prevent tail-to-tail agglutination of sperm during storage in the epididymis.
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PMID:Maturation antigen of the mouse sperm flagellum. I. Analysis of its secretion, association with sperm, and function. 327 44

The most abundant protein in fluid from the mouse cauda epididymidis, designated CP 27, is a glycoprotein that migrates at approximately 27000 daltons on SDS-polyacrylamide gels. Samples of CP 27 were isolated by preparative gel electrophoresis and were used to raise a guinea-pig polyclonal antiserum, which reacted with a single band on western blots of caudal epididymal fluid. This antiserum was used for immunocytochemical localization of CP 27 in histological sections of mouse epididymis using the peroxidase-antiperoxidase and protein A-gold methods. The most proximal staining with anti-CP 27 was in segment 6 of the distal caput epididymidis, where the lumen and a portion of the supranuclear cytoplasm of principal cells were stained. In contrast, in the distal corpus and cauda epididymidis (segments 8-11), there was pronounced staining of the luminal contents, sterocilia, and scattered cells identified as the "light" cells of the epididymal epithelium. Although CP 27 was found in the epididymal lumen of all segments distal to segment 6, the intensity of staining appeared to decline distally in the cauda epididymidis. Control sections exposed to pre-immune serum instead of anti-CP 27 showed no reaction. The results suggest that CP 27, the major glycoprotein of cauda epididymal fluid, is synthesized by principal cells of segment 6 of the distal caput epididymidis. CP 27 may be among the substances absorbed from the lumen by the light cells of the distal epididymis.
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PMID:Immunocytochemical localization of the major glycoprotein of epididymal fluid from the cauda in the epithelium of the mouse epididymis. 328 51

Previously, we demonstrated that surface radiolabeling of rat epididymal spermatozoa by lactoperoxidase-catalyzed iodination reveals a major component with an apparent molecular weight of 26,000 to 28,000 daltons (26 kDa) on spermatozoa from the cauda but not the caput epididymidis. To characterize this surface component further, sperm surface constituents radiolabeled by lactoperoxidase-catalyzed iodination were separated by 2-D PAGE. The 26 kDa component was localized by autoradiography and appeared as the major labeled acidic spot on cauda spermatozoa, but neither a radiolabeled spot nor a corresponding stained spot was present on caput spermatozoa. The 26 kDa spot was excised from 2-D gels of plasma membranes from cauda spermatozoa and utilized for immunization. The monospecific antiserum stained a single band of 26 kDa on Western blots of SDS-PAGE-separated plasma membranes from cauda spermatozoa and in a 100,000 X g supernatant fluid of the luminal contents of the cauda epididymidis. Immunohistochemical staining of cauda spermatozoa revealed antigen exclusively on the flagellar domain; the antigen was not seen on caput spermatozoa but first appeared in spermatozoa from the proximal corpus epididymidis. Immunoelectron microscopy confirmed the 26 kDa component was localized to the external face of the flagellar plasma membrane. Immunohistochemical staining of caput spermatozoa incubated in vitro with cauda epididymal luminal fluid revealed the 26 kDa component specifically bound the flagellar domain of immature spermatozoa.
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PMID:Modification of the rat sperm flagellar plasma membrane during maturation in the epididymis. 330 69


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