Stimulation of insulin release from permeabilized HIT-T15 cells by a synthetic peptide corresponding to the effector domain of the small GTP-binding protein rab3

FEBS Lett. 1993 Jul 26;327(2):145-9. doi: 10.1016/0014-5793(93)80159-r.


A synthetic peptide (rab3AL) corresponding to the effector domain of rab3, a small GTP-binding protein, stimulated basal and potentiated Ca(2+)- as well as GTP gamma S-evoked insulin secretion about 2-fold from streptolysin-O permeabilized HIT cells. This effect was specific, since the analogous peptides of ras or rab1 did not affect the exocytotic event. The more than additive effect of rab3AL on Ca2+ or GTP gamma S stimulation indicates a distinct mode of action of the peptide. The partial loss of cytosolic proteins from permeabilized cells was accompanied by a faster run-down of the secretory response to Ca2+ than the one to GTP gamma S. The persistent effect of rab3AL under these conditions points to a membrane localization of its target. These results suggest that rab3 and its effector are involved in the regulation of insulin secretion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium / pharmacology
  • Cell Line
  • Cell Membrane Permeability
  • Cells, Cultured
  • Electrophoresis, Polyacrylamide Gel
  • Exocytosis / drug effects
  • GTP-Binding Proteins
  • Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology
  • Humans
  • Immunoblotting
  • Insulin / metabolism*
  • Insulin Secretion
  • Nerve Tissue Proteins / chemical synthesis
  • Nerve Tissue Proteins / pharmacology*
  • Peptides / chemical synthesis
  • Peptides / pharmacology
  • Streptolysins
  • rab3 GTP-Binding Proteins


  • Insulin
  • Nerve Tissue Proteins
  • Peptides
  • Streptolysins
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • GTP-Binding Proteins
  • rab3 GTP-Binding Proteins
  • Calcium