High impact information on EXOC3

• The sec6/8 complex or exocyst is an octameric protein complex that functions during cell polarization by regulating the site of exocytic vesicle docking to the plasma membrane, in concert with small GTP-binding proteins [1].
• At the same time, sec6 and sec8, components of a complex critical for basolateral cargo delivery normally arrayed at the apico-lateral apex, were depleted from the ADPKD cell plasma membrane [2].
• Recently the Sec6/8 complex, or exocyst, a multisubunit complex facilitating post-Golgi targeting of distinct subclasses of secretory vesicles, has been identified as a bona fide Ral effector complex [3].
• We demonstrate that oligodendrocytes express several key molecules necessary for the targeting of transport vesicles to areas of rapid membrane growth, including the exocyst components Sec8 and Sec6 and the multidomain scaffolding proteins CASK and Mint1 [4].
• Ultracentrifugation-based approaches to study regulation of Sec6/8 (exocyst) complex function during development of epithelial cell polarity [5].

Biological context of EXOC3

• Consistent with the phenotype of the transgenic mice described above, we found that active but not inactive RalA binds to the Sec6/8 (exocyst) complex, whose yeast counterpart is essential for targeting exocytic vesicles to specific docking sites on the plasma membrane [6].
• Currently, a protein complex, known as the sec6/8 or the exocyst complex, has been implicated to play a role at this late stage of exocytosis [7].
• However, the identity of membrane binding sites for Sec6/8 complex, mechanisms regulating association of Sec6/8 complex with these sites, and the precise function of the complex in polarized trafficking are not known [5].

Other interactions of EXOC3

• We have generated monoclonal antibodies (MAbs) against three proteins sec6, sec15, and exo84 [8].
• The structure of the C-terminal domain of the exocyst subunit Sec6p reveals multiple helical bundles, which are structurally and topologically similar to Exo70p and the C-terminal domains of Exo84p and Sec15, despite <10% sequence identity [9].

References