Functional involvement of Noc2, a Rab27 effector, in rat parotid acinar cells

Arch Biochem Biophys. 2006 Nov 15;455(2):127-35. doi: 10.1016/ Epub 2006 Oct 9.


Noc2 has recently been proposed to regulate exocytosis in both endocrine and exocrine cells; however, protein expression, subcellular localization and function of Noc2 in exocrine cells have never been elucidated. In this study, we investigated whether Noc2, a Rab27 effector, is involved in isoproterenol (IPR)-stimulated amylase release from acinar cells. Rab27 was detected in the apical plasma membrane (APM) and secretory granule membrane (SGM) fractions, and was translocated to the APM after IPR stimulation for 5 min, but was detected at lower levels in the APM after 30 min. In contrast, although Noc2 was expressed in SGM bound to Rab27, Noc2 was not translocated to APM and the Noc2/Rab27 complex was disrupted after stimulation with IPR for short time. In addition, the anti-Noc2-Rab-binding-domain antibody inhibited IPR-stimulated amylase release from streptolysin O-permeabilized parotid acinar cells. Our results suggest that the Noc2/Rab27 complex is an important constituent of the early stages of IPR-stimulated amylase release.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Intracellular Signaling Peptides and Proteins
  • Isoproterenol / administration & dosage*
  • Parotid Gland / drug effects
  • Parotid Gland / metabolism*
  • Protein Transport / drug effects
  • Protein Transport / physiology
  • Proteins / metabolism*
  • Rats
  • Signal Transduction / drug effects
  • Signal Transduction / physiology*
  • rab GTP-Binding Proteins / metabolism*
  • rab27 GTP-Binding Proteins


  • Intracellular Signaling Peptides and Proteins
  • Proteins
  • Rph3al protein, rat
  • rab27 GTP-Binding Proteins
  • Rab27a protein, rat
  • rab GTP-Binding Proteins
  • Isoproterenol