Ral: mediator of membrane trafficking

Int J Biochem Cell Biol. 2006;38(11):1841-7. doi: 10.1016/j.biocel.2006.04.006. Epub 2006 May 9.

Abstract

Ral is a multifunctional small GTPase involved in tumorigenesis and in controlling intracellular membrane trafficking. It is mainly activated by factors downstream of Ras, or independently of these factors and operates by protein-protein interactions with an expanding repertoire of partners. RalA is a positive regulator of calcium-evoked exocytosis via binding phospholipase D and is involved in G protein coupled receptor signalling by binding phospholipase C-delta1. The binding of Ral to calmodulin links to intracellular trafficking events. Another link is direct binding of activated Ral (Ral-GTP) to the endocytic and exocytic machineries. Ral-GTP binds RalBP1, which connects to receptor-mediated endocytosis via AP-2. Alternatively, Ral-GTP binds the exocyst complex, which controls secretory vesicle trafficking in regulated secretion and filopodia formation. Thus, Ral-GTP "chooses" between different membrane trafficking pathways. Other Ral partners are still being uncovered that may provide further mechanistic insights into how Ral controls diverse membrane trafficking pathways.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Biological Transport
  • Cell Membrane / metabolism*
  • Humans
  • Models, Biological
  • Molecular Sequence Data
  • Protein Binding
  • Sequence Homology, Amino Acid
  • ral GTP-Binding Proteins / genetics
  • ral GTP-Binding Proteins / metabolism
  • ral GTP-Binding Proteins / physiology*

Substances

  • ral GTP-Binding Proteins