A novel 145 kd brain cytosolic protein reconstitutes Ca(2+)-regulated secretion in permeable neuroendocrine cells

Cell. 1992 Sep 4;70(5):765-75. doi: 10.1016/0092-8674(92)90310-9.


The regulated secretory pathway is activated by elevated cytoplasmic Ca2+; however, the components mediating Ca2+ regulation have not been identified. In semi-intact neuroendocrine cells, Ca(2+)-activated secretion is ATP- and cytosol protein-dependent. We have identified a novel brain protein, p145, as a cytosolic factor that reconstitutes Ca(2+)-activated secretion in two neuroendocrine cell types. The protein is a dimer of 145 kd subunits, exhibits Ca(2+)-dependent interaction with a hydrophobic matrix, and binds phospholipid vesicles, suggesting a membrane-associated function. A p145-specific antibody inhibits the reconstitution of Ca(2+)-activated secretion by cytosol, indicating an essential role for p145. The restricted expression of p145 in tissues exhibiting a regulated secretory pathway suggests a key role for this protein in the transduction of Ca2+ signals into vectorial membrane fusion events.

Publication types

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

MeSH terms

  • Animals
  • Brain Chemistry
  • Calcium / metabolism*
  • Calcium-Binding Proteins*
  • Cytosol / chemistry
  • Exocytosis
  • Molecular Weight
  • Nerve Tissue Proteins / isolation & purification*
  • Nerve Tissue Proteins / pharmacology
  • Norepinephrine / metabolism
  • PC12 Cells / drug effects*
  • Rats


  • Cadps protein, rat
  • Calcium-Binding Proteins
  • Nerve Tissue Proteins
  • Calcium
  • Norepinephrine