Synthetic peptides of the effector-binding domain of rab enhance secretion from digitonin-permeabilized chromaffin cells

FEBS Lett. 1992 Aug 31;309(1):41-6. doi: 10.1016/0014-5793(92)80735-y.

Abstract

There is evidence that the rab class of low molecular weight GTP-binding proteins is involved in vesicular transfer from endoplasmic reticulum to Golgi and between Golgi cisternae. To determine whether similar proteins play a role in regulated exocytosis, the effects of synthetic peptides derived from low molecular weight GTP-binding proteins on catecholamine secretion from digitonin-permeabilized chromaffin cells were investigated. The synthetic peptides represent the putative effector-binding domains of the rab, ras and ral classes of low molecular weight GTP-binding proteins and correspond to ras(33-48). Two rab peptides but neither a ras nor a ral peptide enhanced Ca(2+)-dependent secretion by approximately 30%. Maximal secretion in response to Ca2+ was increased. The enhancement was not blocked by the pseudosubstrate inhibitor of protein kinase C, PKC(19-31), thus indicating that activation of protein kinase C was not responsible for the enhancement of secretion. Similarly a rab peptide but neither a ras nor a ral peptide enhanced GppNHp-induced secretion 30-70%. The peptides had little or no effect in the absence of Ca2+ or GppNHp. The data are consistent with a protein of the rab class playing a role in regulated exocytosis.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Adrenal Medulla / drug effects
  • Adrenal Medulla / metabolism*
  • Amino Acid Sequence
  • Animals
  • Calcium / pharmacology
  • Cattle
  • Cell Membrane Permeability / drug effects
  • Digitonin
  • GTP-Binding Proteins / metabolism*
  • Guanylyl Imidodiphosphate / pharmacology
  • Models, Biological
  • Molecular Sequence Data
  • Nerve Tissue Proteins / metabolism*
  • Nerve Tissue Proteins / pharmacology
  • Peptide Fragments / pharmacology*
  • rab3 GTP-Binding Proteins

Substances

  • Nerve Tissue Proteins
  • Peptide Fragments
  • Guanylyl Imidodiphosphate
  • Adenosine Triphosphate
  • GTP-Binding Proteins
  • rab3 GTP-Binding Proteins
  • Digitonin
  • Calcium