nicholas-andersen@uiowa.edu
Mentor: Charles Yeaman, Ph.D.
Lab Phone: 384-4639

Tethering complexes are essential for vesicular transport in both secretory and endocytic pathways. Structurally diverse tethering complexes are hypothesized to link vesicles to their target membrane in a manner that induces the assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex composed of SNARE proteins on the vesicle (v-SNARE) and target membrane (t-SNARE). It is not known how tethering complexes facilitate SNARE assembly and final membrane fusion.

The sec6/8 complex (exocyst) is an eight subunit complex that acts by tethering post-Golgi vesicles to the plasma membrane. Sec3 is a 102kD protein subunit of the exocyst. The sec3 protein contains a coiled-coil motif on its amino terminus that is structurally homologous to the v-SNARE family of VAMPs. We hypothesize sec3 interacts directly to syntaxin 4 on the plasma membrane via the VAMP-like coiled-coil. This interaction may then present syntaxin 4 to the v-SNARE resulting in SNARE complex assembly and membrane fusion.



Abstracts: Spiczka, K., Anderson, N., and Yeaman, C. Changes in Inter-subunit Interactions Accompany Exocyst Recruitment to Plasma Membrane and Correlate with its Activity. Molecular Biology of the Cell 192, 2008.

Andersen NJ , Yeaman, C, Sec3-containing exocyst complex is required for desmosome assembly in mammalian epithelial cells. Mol Biol Cell. 2010 Jan 1;21(1):152-64. Epub 2009 Nov 4. PubMed PMID: 19889837; PubMed Central PMCID: PMC2801709.