The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
Gene Review

LOC373457  -  speract protein

Strongylocentrotus purpuratus

 
 
Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.
 

High impact information on LOC373457

  • A. punctulata spermatozoa do not respond to speract, a peptide isolated from the jelly layer of Strongylocentrotus purpuratus eggs [1].
  • Activation of Na+:H+ exchange without speract by either Na+ addition to sperm in Na+-free seawater (NaFASW) or by monensin also increases [Ca2+]i, but neither change is transient [2].
  • Increasing pHi by adding 10 mM NH4+ or by addition of Li+ to sperm in NaFASW does not increase [Ca2+]i. The data suggest that speract binding leads to rapid activation of Na+:H+ exchange; and, as a consequence, [Ca2+] entry increases transiently through either Na+:Ca2+ exchange or else through a verapamil-insensitive Ca2+ channel [2].
  • However, membrane potential depolarization did not occur when the activation was induced by increased extracellular pH or by the peptide speract, although activation was always linked to increased intracellular pH [3].
  • The peptide, purified from Strongylocentrotus purpuratus eggs, also cross-reacts with spermatozoa from Lytechnis pictus sea urchins, suggesting that speract does not show species specificity [4].
 

Biological context of LOC373457

  • A complementary DNA clone (2.3 kb) that encodes the egg peptide speract (Gly-Phe-Asp-Leu-Asn-Gly-Gly-Gly-Val-Gly) has been isolated from an ovary cDNA library of the sea urchin [5].
  • Inhibition of Na+:H+ exchange by increased seawater [K+] prevents the rise in [Ca2+]i initiated by either speract or Na+ addition to sperm in NaFASW [2].
  • Speract is a potent stimulator of sea urchin sperm oxygen consumption, causing significant increases of sperm respiration rates at concentrations as low as 10(-12) M and producing 20-fold increases of oxygen consumption at maximal concentrations of 10(-8) M [4].
  • Speract, a peptide of S. purpuratus may act as a chemoattractant as well or may serve functions other than chemotaxis [6].
  • Competition binding studies with the fluorescent peptide and intact spermatozoa yielded IC50 values which were indistinguishable from native speract and GGG[Y2]-speract (approximately 20 nM) [7].
 

Anatomical context of LOC373457

 

Associations of LOC373457 with chemical compounds

  • An apparent receptor for the egg peptide speract (Gly-Phe-Asp-Leu-Asn-Gly-Gly-Gly-Val-Gly) was identified by covalently coupling a radiolabeled speract analogue to intact spermatozoa and was then purified by DEAE-Sepharose chromatography and preparative gel electrophoresis after solubilization with Lubrol PX [9].
  • Sperm cyclic GMP and cyclic AMP concentrations are also increased by speract, but concentrations of at least 10(-10) M and 10(-9) M are required for half-maximal elevations, respectively [4].
  • A low molecular weight peptide (speract) associated with sea urchin eggs has been purified to apparent homogeneity by charcoal adsorption, DEAE-Sephacel chromatography, Bio-Gel P-2 filtration, and Dowex AG 50W-X4 chromatography [4].
  • Speract is composed entirely of neutral and acidic amino acids with glycine as the major component, and it appears to have a blocked NH2 terminus based on its insensitivity to leucine aminopeptidase, its failure to react with dansyl chloride, and its chromatographic behavior on strong cation exchange resins [4].
  • In contrast, hyperpolarization responses to speract are increased by 3-isobutyl-1-methylxanthine, which preferentially inhibits cGMP-selective phosphodiesterases of sperm, and the 8Br-cGMP derivative hyperpolarizes vesicles in the absence of speract [10].

References

  1. Chemotaxis of Arbacia punctulata spermatozoa to resact, a peptide from the egg jelly layer. Ward, G.E., Brokaw, C.J., Garbers, D.L., Vacquier, V.D. J. Cell Biol. (1985) [Pubmed]
  2. Alteration of intracellular [Ca2+] in sea urchin sperm by the egg peptide speract. Evidence that increased intracellular Ca2+ is coupled to Na+ entry and increased intracellular pH. Schackmann, R.W., Chock, P.B. J. Biol. Chem. (1986) [Pubmed]
  3. Measurement of plasma membrane and mitochondrial potentials in sea urchin sperm. Changes upon activation and induction of the acrosome reaction. Schackmann, R.W., Christen, R., Shapiro, B.M. J. Biol. Chem. (1984) [Pubmed]
  4. Speract. Purification and characterization of a peptide associated with eggs that activates spermatozoa. Hansbrough, J.R., Garbers, D.L. J. Biol. Chem. (1981) [Pubmed]
  5. A single mRNA encodes multiple copies of the egg peptide speract. Ramarao, C.S., Burks, D.J., Garbers, D.L. Biochemistry (1990) [Pubmed]
  6. Revisiting the role of H+ in chemotactic signaling of sperm. Solzin, J., Helbig, A., Van, Q., Brown, J.E., Hildebrand, E., Weyand, I., Kaupp, U.B. J. Gen. Physiol. (2004) [Pubmed]
  7. Speract receptors are localized on sea urchin sperm flagella using a fluorescent peptide analog. Cardullo, R.A., Herrick, S.B., Peterson, M.J., Dangott, L.J. Dev. Biol. (1994) [Pubmed]
  8. Co-localization of receptor and transducer proteins in the glycosphingolipid-enriched, low density, detergent-insoluble membrane fraction of sea urchin sperm. Ohta, K., Sato, C., Matsuda, T., Toriyama, M., Vacquier, V.D., Lennarz, W.J., Kitajima, K. Glycoconj. J. (2000) [Pubmed]
  9. Cloning of the mRNA for the protein that crosslinks to the egg peptide speract. Dangott, L.J., Jordan, J.E., Bellet, R.A., Garbers, D.L. Proc. Natl. Acad. Sci. U.S.A. (1989) [Pubmed]
  10. Participation of a K(+) channel modulated directly by cGMP in the speract-induced signaling cascade of strongylocentrotus purpuratus sea urchin sperm. Galindo, B.E., Beltrán, C., Cragoe, E.J., Darszon, A. Dev. Biol. (2000) [Pubmed]
 
WikiGenes - Universities