Involvement of rabphilin-3A in Ca2+-dependent exocytosis from PC12 cells

Biochem Biophys Res Commun. 1996 Feb 15;219(2):435-40. doi: 10.1006/bbrc.1996.0251.


Rabphilin-3A, a putative target molecule of Rab3A small GTP-binding protein implicated in Ca2+-dependent exocytosis, consists of two functionally different domains: the N-terminal Rab3A-binding domain and the C-terminal two C2-like domains (C2A and C2B domains) interacting with Ca2+ and phospholipid. Here, we used the growth hormone (GH) co-expression assay system of PC12 cells in which expressed GH is released in response to high K+. Reduction of endogenous rabphilin-3A inhibited the Ca2+-dependent, high K+-induced GH release. Various rabphilin-3A mutants expressing an N-terminal, C-terminal, or C2B fragment, but not the rabphilin-3A mutant expressing a C2A fragment, inhibited the high K+-induced GH release. These results indicate that rabphilin-3A is involved at least in Ca2+-dependent exocytosis from PC12 cells and that the C2A and C2B domains have different functions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Amino Acid Sequence
  • Animals
  • Calcium / metabolism*
  • Exocytosis*
  • GTP-Binding Proteins / biosynthesis
  • GTP-Binding Proteins / metabolism*
  • Growth Hormone / biosynthesis
  • Humans
  • Molecular Sequence Data
  • Mutagenesis
  • Mutagenesis, Insertional
  • Nerve Tissue Proteins / biosynthesis
  • Nerve Tissue Proteins / metabolism*
  • PC12 Cells
  • Rats
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / metabolism
  • Sequence Deletion
  • Sequence Tagged Sites
  • Transfection
  • Vesicular Transport Proteins
  • rab GTP-Binding Proteins*


  • Adaptor Proteins, Signal Transducing
  • Nerve Tissue Proteins
  • Recombinant Fusion Proteins
  • Vesicular Transport Proteins
  • rabphilin-3A
  • Growth Hormone
  • GTP-Binding Proteins
  • rab GTP-Binding Proteins
  • Calcium