The exocyst is a Ral effector complex.
Delivery of cytoplasmic vesicles to discrete plasma-membrane domains is critical for establishing and maintaining cell polarity, neurite differentiation and regulated exocytosis. The exocyst is a multisubunit complex required for vectorial targeting of a subset of secretory vesicles. Mechanisms that regulate the activity of this complex in mammals are unknown. Here we show that Sec5, an integral component of the exocyst, is a direct target for activated Ral GTPases. Ral GTPases regulate targeting of basolateral proteins in epithelial cells, secretagogue-dependent exocytosis in neuroendocrine cells and assembly of exocyst complexes. These observations define Ral GTPases as critical regulators of vesicle trafficking.
Moskalenko
Serge
S
Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75235-9039, USA.
Henry
Dale O
DO
Rosse
Carine
C
Mirey
Gladys
G
Camonis
Jacques H
JH
White
Michael A
MA
D000818:Animals; D018938:Caco-2 Cells; D002352:Carrier Proteins / Q000502:physiology; D016764:Cell Polarity / Q000502:physiology; D005089:Exocytosis / Q000502:physiology*; D005656:Fungal Proteins / Q000502:physiology; D020690:GTPase-Activating Proteins; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology*; D016716:PC12 Cells; D010739:Phospholipase D / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D022142:Secretory Vesicles / Q000502:physiology; D015398:Signal Transduction; D033921:Vesicular Transport Proteins; D020725:ral GTP-Binding Proteins / Q000502:physiology*
D002352:Carrier Proteins; C511410:Exoc2 protein, rat; D005656:Fungal Proteins; D020690:GTPase-Activating Proteins; D008565:Membrane Proteins; C094755:Ralbp1 protein, rat; D033921:Vesicular Transport Proteins; D010739:Phospholipase D; C106801:phospholipase D1; D020725:ral GTP-Binding Proteins