Small G proteins as key regulators of pancreatic digestive enzyme secretion

John A. Williams, Xuequn Chen, Maria E. Sabbatini

Research output: Contribution to journalReview articlepeer-review

41 Scopus citations


Small GTP-binding (G) proteins act as molecular switches to regulate a number of cellular processes, including vesicular transport. Emerging evidence indicates that small G proteins regulate a number of steps in the secretion of pancreatic acinar cells. Diverse small G proteins have been localized at discrete compartments along the secretory pathway and particularly on the secretory granule. Rab3D, Rab27B, and Rap1 are present on the granule membrane and play a role in the steps leading up to exocytosis. Whether the function of these G proteins is simply to ensure appropriate targeting or if they are involved as regulatory molecules is discussed. Most evidence suggests that Rab3D and Rab27B play a role in tethering the secretory granule to its target membrane. Other Rabs have been identified on the secretory granule that are associated with different steps in the secretory pathway. The Rho family small G proteins RhoA and Rac1 also regulate secretion through remodeling of the actin cytoskeleton. Possible mechanisms for regulation of these G proteins and their effector molecules are considered.

Original languageEnglish (US)
Pages (from-to)E405-E414
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Issue number3
StatePublished - Mar 2009
Externally publishedYes


  • Actin cytoskeleton
  • Rab
  • Rac
  • Rap
  • Rho
  • Secretory granule
  • Vesicular transport

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)


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