A novel Ca2+-binding protein, p22, is required for constitutive membrane traffic

Academic Article


  • We have identified a novel protein, p22, required for "constitutive" exocytic membrane traffic. p22 belongs to the EF-hand superfamily of Ca2+-binding proteins and shows extensive similarity to the regulatory subunit of protein phosphatase 2B, calcineurin B. p22 is a cytosolic N-myristoylated protein that undergoes conformational changes upon binding of Ca2+. Antibodies against a p22 peptide block the targeting/fusion of transcytotic vesicles with the apical plasma membrane, but recombinant wild-type p22 overcomes that inhibition. Nonmyristoylated p22, or p22 incapable of undergoing Ca2+-induced conformational changes, cannot reverse the antibody-mediated inhibition. The data suggest that p22 may act by transducing cellular Ca2+ signals to downstream effectors. p22 is ubiquitously expressed, and we propose that its function is required for membrane trafficking events common to many cells.
  • Published In

    Digital Object Identifier (doi)

    Author List

  • Barroso MR; Bernd KK; DeWitt ND; Chang A; Mills K; Sztul ES
  • Start Page

  • 10183
  • End Page

  • 10187
  • Volume

  • 271
  • Issue

  • 17