Calmodulin is the divalent cation receptor for rapid endocytosis, but not exocytosis, in adrenal chromaffin cells

Neuron. 1996 Jan;16(1):195-205. doi: 10.1016/s0896-6273(00)80036-7.

Abstract

Exocytosis and the ensuing rapid endocytosis in adrenal chromaffin cells are both Ca(2+)-dependent phenomena but differ in their divalent cation specificity, implying distinct Ca2+ receptors for the two processes. To ascertain whether calmodulin is the Ca2+ receptor for either process, we blocked its function by introducing calmodulin-binding peptides or anti-calmodulin antibodies into these cells. Exo/endocytosis was followed by measurement of cell membrane capacitance. Rapid endocytosis, but not exocytosis, was abolished by these treatments, indicating that calmodulin is the Ca2+ receptor for rapid endocytosis but is not involved in exocytosis. The principal calmodulin target is not protein phosphatase-2B, as antagonism of this enzyme did not inhibit but accelerated rapid endocytosis. Calmodulin may thus regulate both the rate and extent of rapid endocytosis by distinct pathways.

Publication types

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

MeSH terms

  • Adrenal Medulla / cytology
  • Adrenal Medulla / metabolism*
  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / immunology
  • Antibodies, Monoclonal / pharmacology
  • Barium / pharmacology
  • Calcineurin
  • Calcium / physiology*
  • Calcium-Binding Proteins / drug effects
  • Calcium-Binding Proteins / physiology*
  • Calmodulin / antagonists & inhibitors
  • Calmodulin / immunology
  • Calmodulin / physiology*
  • Calmodulin-Binding Proteins / antagonists & inhibitors
  • Cattle
  • Endocytosis / physiology*
  • Enzyme Inhibitors / pharmacology
  • Exocytosis*
  • Manganese / pharmacology
  • Membrane Potentials / drug effects
  • Molecular Sequence Data
  • Peptide Fragments / immunology
  • Phosphoprotein Phosphatases / antagonists & inhibitors
  • Protein Kinase Inhibitors
  • Strontium / pharmacology

Substances

  • Antibodies, Monoclonal
  • Calcium-Binding Proteins
  • Calmodulin
  • Calmodulin-Binding Proteins
  • Enzyme Inhibitors
  • Peptide Fragments
  • Protein Kinase Inhibitors
  • Barium
  • Manganese
  • Calcineurin
  • Phosphoprotein Phosphatases
  • Calcium
  • Strontium