Time-resolved sperm responses to an egg peptide measured by stopped-flow fluorometry

Biochem Biophys Res Commun. 2001 Jun 8;284(2):531-5. doi: 10.1006/bbrc.2001.5000.

Abstract

Speract, a decapeptide from sea urchin egg jelly, induces various sperm responses. Stopped-flow fluorometry was used to examine the binding of labeled speract and the intracellular changes in pH (pH(i)) and Ca2+ ([Ca2+]i) it induces in sperm. We observed significant time delays for the increase in pH(i) and [Ca2+]i induced by 200 nM speract (69 and 190 ms, respectively). Also, we found that the receptor undergoes a pH(i)-dependent affinity change at around 129 ms. These time delays probably reflect biochemical processes underlying each sperm response to speract that circumscribe the time sequence of the signaling events.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism
  • Chemotaxis / drug effects
  • Fluorescent Dyes / chemistry
  • Fluorometry / methods
  • Hydrogen-Ion Concentration / drug effects
  • Intracellular Fluid / metabolism
  • Male
  • Oligopeptides / chemistry
  • Oligopeptides / pharmacology*
  • Protein Binding / physiology
  • Reaction Time / drug effects
  • Receptors, Cell Surface / metabolism
  • Sea Urchins
  • Signal Transduction / drug effects
  • Signal Transduction / physiology
  • Spermatozoa / cytology
  • Spermatozoa / drug effects*
  • Spermatozoa / metabolism*

Substances

  • Fluorescent Dyes
  • Oligopeptides
  • Receptors, Cell Surface
  • egg surface sperm receptor
  • speract
  • Calcium