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)

Hyaluronidase release was used as an index of acrosomal membrane damage during cold shock of epididymal boar sperm and ejaculated sperm from intact and vesiculectomized boars. Sperm were also incubated with seminal plasma from intact and vasectomized boars to examine the contributions of male accessory gland secretions. Acrosomal membranes of epididymal sperm were more resistant to cold shock than those of ejaculated sperm. Only 36% of the hyaluronidase released by ejaculated sperm was released by the epididymal sperm in spite of similar hyaluronidase content of the sperm. Preincubation of epididymal sperm in seminal plasma from both intact and vasectomized boars increased resistance to cold shock by 60 to 80%. Initial dilution of epididymal sperm with seminal plasma, rather than Ringer-fructose buffer, was associated with low progressive motility and with retention of cytoplasmic droplets. In contrast, acrosomal membranes of ejaculated sperm from intact and vesiculectomized boars exhibited similar sensitivity to cold shock, releasing hyaluronidase capable of forming .20 and .19 mumol N-acetylglucosamine from hyaluronic acid/10(8) sperm in 8 min. Moreover, seminal plasma from vasectomized boars had no effect on acrosomal sensitivity to cold shock of ejaculated sperm from vesiculectomized boars.
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PMID:Effect of male accessory gland secretions on sensitivity of porcine sperm acrosomes to cold shock, initiation of motility and loss of cytoplasmic droplets. 400 68

We have identified an 80 kDa protein in ejaculated bull spermatozoa (p80) which is found in acrosomal and post-acrosomal areas of the head. It has a hyaluronidase activity and shares homologies with PH-20, a sperm surface glycoprotein involved in sperm-egg interaction. The aim of the present study was to characterize bull sperm p80 protein at the nucleic and amino acid levels to determine whether it is the bovine PH-20 ortholog. The complete nucleotide sequence determined by RT-PCR, 3' and 5' RACE show that bull p80, displays identity with the PH-20 nucleotide and amino acid sequences. Messenger RNA and protein expressions determined by Northern blot and immunohistochemistry revealed that the protein is testicular (expressed in spermatocytes and spermatids). The localization of p80 on spermatozoa, determined by indirect immunofluorescence using a monoclonal antibody, shows the protein in acrosomal and post acrosomal areas of the head with an increase in the signal intensity as sperm progress through the epididymis. Post-translational modifications of the protein were investigated during the epididymal maturation by Western blot on protein extracts from sperm collected in the caput, corpus and cauda portions of bull epididymis. Glycolysation status of sperm p80 protein on proteins from ejaculated and epididymidal sperm was investigated. Result show that the glycosylation status is modified as spermatozoa migrate through the epididymis. Hyaluronidase activity evaluated in protein extracts from spermatozoa of the three different epididymal sections revealed that the activity is higher at pH 7 than 4 and is not affected by epididymal maturation. These data strongly suggest that p80 is the bovine PH-20.
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PMID:Identification of the bull sperm p80 protein as a PH-20 ortholog and its modification during the epididymal transit. 1589 45

Sperm adhesion molecule 1 (SPAM1), is a glycosyl phoshatidylinositol-linked sperm membrane protein that is dually expressed in testis and epididymis. Epididymal SPAM1 is secreted in all three regions of the epididymis in all mammalian species studied, including humans. It shares the same molecular mass and neutral hyaluronidase activity as the testicular and sperm isoforms that are responsible for the penetration of the cumulus during fertilization. Using wild-type (W/T) sperm and those from mice homozygous for either a null (Spam1-/-) or mutant Spam1 allele, which results in decreased mRNA and protein, we demonstrate that sperm binding of epididymal SPAM1 occurs in vitro after exposure to W/T sperm-free epididymal luminal fluid (ELF). Binding or adsorption that occurred after incubation at room temperature or 32 degrees C was detected immunocytochemically and confirmed quantitatively using flow cytometry. The localization of SPAM1 on the plasma membrane of Spam1-null sperm mimicked that seen in the W/T. The remarkable increase in binding on W/T caudal sperm indicates that they are not fully saturated with SPAM1 during storage, and suggests that uptake of epididymal SPAM1 in vivo augments testicular SPAM1. Spam1-null sperm exposed to W/T ELF for 45-60 min during in vitro capacitation to allow epididymal SPAM1 binding showed a highly significant (P < 0.001) increase in cumulus penetration after 6-7 h compared to those incubated in ELF from null males. Similarly, the number of cumulus-free oocytes was also highly significantly greater (P < 0.001) than that for sperm capacitated in W/T SPAM1-antibody-inhibited ELF. Because epididymal SPAM1 uptake significantly increases cumulus penetration, we conclude that it is a marker of sperm maturation.
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PMID:Epididymal SPAM1 is a marker for sperm maturation in the mouse. 1643 26

The molecular mechanisms underlying sperm penetration of the physical barriers surrounding the oocyte have not been completely delineated. Although neutral-active or "reproductive" hyaluronidases (hyases), exemplified by Sperm Adhesion Molecule 1 (SPAM1), are thought to be responsible for hyaluronan digestion in the egg vestments and for sperm-zona binding, their roles in mouse sperm have been recently questioned. Here we report that acidic "somatic" Hyaluronidase 3 (HYAL3), a homolog of SPAM1 with 74.6% structural similarity, exists in two isoforms in human ( approximately 47 and approximately 55 kDa) and mouse ( approximately 44 and approximately 47 kDa) sperm, where it resides on the plasma membrane over the head and midpiece. Mouse isoforms are differentially distributed in the soluble (SAP), membrane (MBP), and acrosome-reacted (AR) fraction where they are most abundant. Comparisons of zymography of Hyal3 null and wild-type (WT) AR and MBP fractions show significant HYAL3 activity at pH 3 and 4, and less at pH 7. At pH 4, a second acid-active hyase band at approximately 57 kDa is present in the AR fraction. HYAL3 activity was confirmed using immunoprecipitated HYAL3 and spectrophotometry. In total proteins, hyase activity was higher at pH 6 than at 4, where Spam1 nulls had significantly (P < 0.01) diminished activity implicating an acidic optima for murine SPAM1. Although fully fertile, Hyal3 null sperm showed delayed cumulus penetration and reduced acrosomal exocytosis. HYAL3 is expressed in epididymal tissue/fluid, from where it is acquired by caudal mouse sperm in vitro. Our results reveal concerted activity of both neutral- and acid-active hyaluronidases in sperm.
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PMID:Acidic hyaluronidase activity is present in mouse sperm and is reduced in the absence of SPAM1: evidence for a role for hyaluronidase 3 in mouse and human sperm. 2058 96

To initiate the crucial cell adhesion events necessary for fertilization, sperm must penetrate extracellular matrix barriers containing hyaluronic acid (HA), a task thought to be accomplished by neutral-active hyaluronidases. Here we report that the ~57 kDa hyaluronidase 2 (HYAL2) that in somatic tissues has been highly characterized to be acid-active is present in mouse and human sperm, as detected by Western blot, flow cytometric, and immunoprecipitation assays. Immunofluorescence revealed its presence on the plasma membrane over the acrosome, the midpiece, and proximal principal piece in mice where protein fractionation demonstrated a differential distribution in subcellular compartments. It is significantly more abundant in the acrosome-reacted (P = 0.04) and soluble acrosomal fractions (P = 0.006) (microenvironments where acid-active hyaluronidases function) compared to that of the plasma membrane where neutral hyaluronidases mediate cumulus penetration. Using HA substrate gel electrophoresis, immunoprecipitated HYAL 2 was shown to have catalytic activity at pH 4.0. Colocalization and coimmunoprecipitation assays reveal that HYAL2 is associated with its cofactor, CD44, consistent with CD44-dependent HYAL2 activity. HYAL2 is also present throughout the epididymis, where Hyal2 transcripts were detected, and in the epididymal luminal fluids. In vitro assays demonstrated that HYAL2 can be acquired on the sperm membrane from epididymal luminal fluids, suggesting that it plays a role in epididymal maturation. Because similar biphasic kinetics are seen for HYAL2 and SPAM1 (Sperm adhesion molecule 1), it is likely that HYAL2 plays a redundant role in the catalysis of megadalton HA to its 20 kDa intermediate during fertilization.
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PMID:Hyaluronidase 2: a novel germ cell hyaluronidase with epididymal expression and functional roles in mammalian sperm. 2523 17