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)

Biochemical, immunological, and electron microscopic methods have been used to provide semi-quantitative estimates and to localize actin in membranes of boar spermatozoa. Immunoblots, using a monoclonal antibody raised against actin from chicken gizzard, detected the protein in caput and cauda sperm plasma membranes. Immunoassay indicated that approximately 1% of the total plasma membrane protein was actin. Monomeric actin accounted for more than one-half of the membrane actin. Approximately 30-40% of plasma membrane actin was insoluble in Triton X-100, and approximately 10% of the total actin remained insoluble after treatment with guanidine hydrochloride. The presence of F-actin in sperm plasma membranes and in plasma membrane detergent-insoluble proteins was detected by fluorescence microscopy using the specific probe NBD phallacidin. When S1 myosin subfragments attached to colloidal gold were used to localize F-actin by electron microscopy, the label was restricted to the outer acrosomal membrane of intact epididymal and ejaculated sperm. Filaments appeared in short arrays along the anterior region of the membrane. S1/gold labeled detergent-insoluble plasma membrane fractions but did not label the plasma membrane in intact sperm. Filaments were least prominent in intact caput spermatozoa and most prominent in ejaculated spermatozoa. We conclude that most actin associated with sperm membranes is in monomeric form in boar spermatozoa, but that actin filaments or protofilaments are components of the outer acrosomal membrane. These filaments may also associate with the plasma membrane overlying the acrosome.
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PMID:Characterization of membrane-associated actin in boar spermatozoa. 231 48

During attempts to isolate bovine sperm actin, persistent low molecular weight proteinaceous (LMWP) contaminants were found. A LMWP fraction was prepared by gel filtration chromatography on Sephadex G150. The LMWP was found in extracts of washed bovine ejaculated spermatozoa and in clarified bovine seminal plasma. It was substantially reduced in amount in bovine epididymal spermatozoa, indicating that it originated from secondary sex gland secretions. The LMWP inhibited rabbit muscle actin-stimulated myosin adenosine triphosphatase (actin-myosin ATPase) activity. The LMWP:actin ratio for 50% inhibition of actin-myosin ATPase was 2.6 +/- 0.12 mg LMWP per mg actin. The LMWP interfered with actin inhibition of deoxyribonuclease, indicating that LMWP interacted with actin. The LMWP from seminal plasma had an estimated molecular weight of 8300 and consisted of several acidic components. It had negligible protease activity and its inhibition of actin-myosin ATPase was independent of divalent cations. The LMWP appears to readily aggregate with itself and other proteins, which may be related to its physiological role in semen.
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PMID:A bovine seminal plasma inhibitor of actin-stimulated myosin adenosine triphosphatase. 622 26

Mechanical responses to noradrenaline (NA) were investigated in the rat vas deferens exposed to Ca-free solution containing 0.5 mM-EGTA. A tonic response was produced in Ca-free solution at the epididymal portion, while almost no response could be observed at the prostatic portion. In most experiments NA (10(-4) M) was applied for 4 min, every 20 min. The absolute tension development in Ca-free solution was usually 60-80% of the control tonic response in the presence of 2.4 mM-Ca. The response could be produced repeatedly, even after exposure to Ca-free solution for more than 20 hr, without a significant decrease. During the first hour of exposure to Ca-free solution, the rate of rise and the magnitude of the NA contraction increased and then remained constant, though the relaxation became slow. Transient treatment with 2.4 mM-Ca slightly suppressed the subsequent NA response in Ca-free solution. Similarly, the NA response was smaller during readmission of 0.2-0.5 mM-Ca than that obtained before Ca readmission. A high concentration of verapamil (2 X 10(-4) M) reversibly reduced the NA response by about 70% after 30 min. Theophylline (10 mM) and dibutyryl cyclic AMP (10(-4) M) also reversibly suppressed the NA response, the suppression being about 80%. None of these substances produced a tension change by themselves. The suppressing effect may be mediated via an increase of intracellular cyclic AMP which reduces phosphorylation of myosin. Caffeine (10 mM) and dibutyryl cyclic GMP (10(-4) M) had similar but much weaker effects than theophylline and dibutyryl cyclic AMP. A calmodulin antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalene sulphonamide (W-7) slowly reduced the NA response. The block was nearly complete after 30 min treatment with 3 X 10(-4) M-W-7, and the recovery was very poor after prolonged exposure. This effect of W-7, which is the same in the presence and absence of Ca, suggests that a Ca-calmodulin reaction is involved in the NA response in Ca-free solution. Fluoride at a concentration higher than 3 mM increased the muscle tone in the absence of external Ca, and transiently potentiated the NA response. In the presence of F-, the relaxation of the NA response was incomplete and the muscle tone increased stepwise after each NA application. When the muscle tone became higher than the NA response in the absence of F-, the NA response was abolished. The action of several metabolic inhibitors (2,4-dinitrophenol, carbonylcyanide chlorophenyl hydrazone, NaCN, monoiodoacetate) was similar to that of F-, suggesting that they release Ca from mitochondria, causing tension development. The observations are consistent with the hypothesis that the contraction of the vas deferens caused by NA in the absence of external Ca depends on the availability of intracellular Ca, stored in mitochondria and released by NA.
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PMID:Mechanical response to noradrenaline in calcium-free solution in the rat vas deferens. 630 44

The anatomical distribution of smooth muscle actin, myosin, fibronectin and basement membrane has been investigated immunohistochemically, using the indirect immunofluorescence technique, in the rat epididymis. The findings were correlated with the ultrastructural organization of the organ. Actin was found to be distributed in the stereociliary region of the epithelial principal cells and in the terminal web region. Actin was also visible along the base of the epithelium. Myosin was detected in the terminal web and in the terminal bar regions of the epithelium. The contractile cells showed a strong stain for both proteins. Basement membrane immunoreactivity was distributed along the epithelial basement membrane and around the contractile cells of the wall. In the cauda, between the epithelium and the contractile cell layers, the lamina propria, containing blood vessels and a thin layer of cells, was negative for all antigens investigated. Fibronectin showed a granular distribution around the contractile cells, mainly in the cauda. The ultrastructural study showed only thin (5-6 nm in diameter) filaments in the stereocilia and terminal web region. Thin filaments were also visible in the cytoplasm of the basal cells, thus suggesting a contractile function of this cell type. The heterogeneous appearance of the contractile cells of the wall seemed to support the different contractile pattern of the epididymal regions: caput, corpus and cauda. The cells present in the lamina propria showed cytoplasmic vesicles with dark granules resembling the "A" cell granules of the endocrine pancreas and gut mucosa cells.
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PMID:Ultrastructural and immunohistochemical studies of rat epididymis. 635 63

We evaluated the effects of three levels of energy intake, 73 % (CON73), 81 % (CON81) and 100 % (CON100) of the ad libitum intake of the control diet, on skeletal muscle growth induced by functional overload in male rats. Unlike most previous studies which have employed chronic or acute food restriction where all nutrients are reduced in the diet, the present study tested the effects of energy deprivation as a single factor without inducing other nutritional deficiencies. Muscular growth of plantaris and soleus muscles was induced by removal of synergist gastrocnemius muscles in one hindlimb; muscles in the other leg were used as sham-operated intra-animal controls. After 30 d, rats on the energy-restricted CON73 and CON81 diets gained less weight and had smaller livers, kidneys, hearts and fat pads (epididymal, retroperitoneal and omental) than CON100 rats They also had smaller sham-operated plantaris muscles (CON73 --13 %, CON81 --9 %) containing less total protein (CON73 --14 %; CON81 --10 %) than CON100 rats However, the same measurements in overloaded plantaris muscles were similar among groups. Soleus muscle mass and protein contents were not significantly affected by energy restriction in our study. Percentage distributions of myosin heavy-chain isoforms (types I, IIa, IIx and IIb) were similar among rats in CON100, CON81 and CON73 groups for both plantaris and soleus muscles. We conclude that the growth reduction of plantaris muscle induced by energy restriction at 73 % and 81 % for 30 d was prevented by functional overload in male rats.
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PMID:The effects of dietary energy restriction on overloaded skeletal muscle in rats. 1117 83

The actin cytoskeleton is the primary polymer system within cells responsible for regulating cellular stiffness. While various actin binding proteins regulate the organization and dynamics of the actin cytoskeleton, the proteins responsible for regulating the mechanical properties of cells are still not fully understood. In the present study, we have addressed the significance of the actin associated protein, tropomyosin (Tpm), in influencing the mechanical properties of cells. Tpms belong to a multi-gene family that form a co-polymer with actin filaments and differentially regulate actin filament stability, function and organization. Tpm isoform expression is highly regulated and together with the ability to sort to specific intracellular sites, result in the generation of distinct Tpm isoform-containing actin filament populations. Nanomechanical measurements conducted with an Atomic Force Microscope using indentation in Peak Force Tapping in indentation/ramping mode, demonstrated that Tpm impacts on cell stiffness and the observed effect occurred in a Tpm isoform-specific manner. Quantitative analysis of the cellular filamentous actin (F-actin) pool conducted both biochemically and with the use of a linear detection algorithm to evaluate actin structures revealed that an altered F-actin pool does not absolutely predict changes in cell stiffness. Inhibition of non-muscle myosin II revealed that intracellular tension generated by myosin II is required for the observed increase in cell stiffness. Lastly, we show that the observed increase in cell stiffness is partially recapitulated in vivo as detected in epididymal fat pads isolated from a Tpm3.1 transgenic mouse line. Together these data are consistent with a role for Tpm in regulating cell stiffness via the generation of specific populations of Tpm isoform-containing actin filaments.
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PMID:Cell elasticity is regulated by the tropomyosin isoform composition of the actin cytoskeleton. 2597 8

Wolffian duct morphogenesis must be highly coordinated with its specialized function of providing an optimal microenvironment for sperm maturation. Without normal Wolffian duct morphogenesis, male infertility will result. Our previous study showed that mediolateral and radial intercalation of epithelial and mesenchymal cells respectively, were major drivers of ductal elongation and were regulated by protein tyrosine kinase 7 (PTK7), a member of the planar cell polarity (PCP) non-canonical Wnt pathway. To understand the mechanism by which PTK7 regulates cell rearrangement/intercalation, we investigated the integrity of the extracellular matrix (ECM) and the activity of intracellular cytoskeleton mediators following loss of Ptk7. Abnormal assembly of nephronectin, laminin, and collagen IV at the basement membrane and fibrosis-like deposition of fibrilla collagen in the interstitium were observed in Ptk7 knockout Wolffian ducts. Further, the activity levels of RAC1 and myosin II, two cytoskeleton mediators, decreased in the Ptk7 knockout mesenchyme compared to controls. In addition, in-vitro experiments suggested that alterations of ECM and cytoskeleton mediators resulted in changes in Wolffian duct morphogenesis. When in-vitro-cultured Wolffian ducts were treated with collagenase IV, the degree of cross-linked fibrilla collagen was reduced, Wolffian duct elongation and coiling were significantly reduced, and an expanded cyst-like duct was observed. When Wolffian ducts were treated with RAC1 inhibitor NSC23766, mesenchymal fibrilla collagen was disassembled, and Wolffian duct elongation was significantly reduced. Our findings provide evidence that PTK7 regulates ECM integrity and the activity levels of RAC1 and myosin II, which in turn regulates Wolffian duct morphogenesis and therefore, epididymal function.
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PMID:Protein tyrosine kinase 7 regulates extracellular matrix integrity and mesenchymal intracellular RAC1 and myosin II activities during Wolffian duct morphogenesis. 2958 Sep 43