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)

The dynamin family of GTPases has been implicated as novel regulators of the acrosome reaction, a unique exocytotic event that is essential for fertilization. Dynamin activity during the acrosome reaction is accompanied by phosphorylation of key serine residues. We now tested the hypothesis that glycogen synthase kinase 3 (GSK3) is the protein kinase responsible for dynamin phosphorylation at these phosphosites in mouse spermatozoa. Pharmacologic inhibition of GSK3 in mature mouse spermatozoa (CHIR99021: IC50 = 6.7 nM) led to a significant reduction in dynamin phosphorylation (10.3% vs. 27.3%; P < 0.001), acrosomal exocytosis (9.7% vs. 25.7%; P < 0.01), and in vitro fertilization (53% vs. 100%; P < 0.01). GSK3 was shown to be present in developing germ cells where it colocalized with dynamin in the peri-acrosomal domain. However, additional GSK3 was acquired by maturing mouse spermatozoa within the male reproductive tract, via a novel mechanism involving direct interaction of sperm heads with extracellular structures known as epididymal dense bodies. These data reveal a novel mode for the cellular acquisition of a protein kinase and identify a key role for GSK3 in the regulation of sperm maturation and acrosomal exocytosis.
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PMID:Glycogen synthase kinase 3 regulates acrosomal exocytosis in mouse spermatozoa via dynamin phosphorylation. 2580 36

The mammalian epididymis is an exceptionally long ductal system tasked with the provision of one of the most complex intraluminal fluids found in any exocrine gland. This specialized milieu is continuously modified by the combined secretory and absorptive of the surrounding epithelium and thus finely tuned for its essential roles in promoting sperm maturation and storage. While considerable effort has been focused on defining the composition of the epididymal fluid, relatively less is known about the intracellular trafficking machinery that regulates this luminal environment. Here, we characterize the ontogeny of expression of a master regulator of this machinery, the dynamin family of mechanoenzymes. Our data show that canonical dynamin isoforms were abundantly expressed in the juvenile mouse epididymis. However, in peripubertal and adult animals dynamin takes on a heterogeneous pattern of expression such that the different isoforms displayed both cell- and segment-specific localization. Thus, dynamin 1 and 3 were predominately localized in the distal epididymal segments (corpus and cauda), where they were found within clear and principal cells, respectively. In contrast, dynamin 2 was expressed throughout the epididymis, but localized to the Golgi apparatus of the principal cells in the proximal (caput) segment and the luminal border of these cells in more distal segments. These dynamin isoforms are therefore ideally positioned to play complementary, nonredundant roles in the regulation of the epididymal milieu. In support of this hypothesis, selective inhibition of dynamin altered the profile of proteins secreted from an immortalized caput epididymal cell line.
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PMID:Developmental expression of the dynamin family of mechanoenzymes in the mouse epididymis. 2839 27

The mammalian epididymis generates one of the most complex intraluminal fluids of any endocrine gland in order to support the post-testicular maturation and storage of spermatozoa. Such complexity arises due to the combined secretory and absorptive activity of the lining epithelial cells. Here, we describe the techniques for the analysis of epididymal protein synthesis and secretion by focusing on the model protein family of dynamin (DNM) mechanoenzymes; large GTPases that have the potential to regulate bi-directional membrane trafficking events. For the study of protein expression in epididymal tissue, we describe robust methodology for immunofluorescence labeling of target proteins in paraffin-embedded sections and the subsequent detection of the spatial distribution of these proteins via immunofluorescence microscopy. We also describe optimized methodology for the isolation and characterization of exosome like vesicles, known as epididymosomes, which are secreted into the epididymal lumen to participate in intercellular communication with maturing sperm cells. As a complementary approach, we also describe the immunofluorescence detection of target proteins in an SV40-immortalized mouse caput epididymal epithelial (mECap18) cell line. Moreover, we discuss the utility of the mECap18 cell line as a suitable in vitro model with which to explore the regulation of epididymal secretory activity. For this purpose, we describe the culturing requirements for the maintenance of the mECap18 cell line and the use of selective pharmacological inhibition regimens that are capable of influencing their secretory protein profile. The latter are readily assessed via harvesting of conditioned culture medium, concentration of secreted proteins via trichloroacetic acid/acetone precipitation and their subsequent analysis via SDS-PAGE and immunoblotting. We contend that these combined methods are suitable for the analysis of alternative epididymal protein targets as a prelude to determining their functional role in sperm maturation and/or storage.
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PMID:Analysis of Epididymal Protein Synthesis and Secretion. 3019 11