Poster: Protein targeting & vesicular trafficking

Abs # 647: Characterization of a putative Arabidopsis sorting nexin

Presenter:	Phan, Nguyen , complex@iastate.edu
Authors	Phan, Nguyen  (A)   Bassham, Diane C. (A)
Affiliations:	(A): Department of Genetics, Developmental and Cellular Biology, Iowa State University, Ames, IA 50010

Protein transport to the vacuole takes place through the secretory pathway. A key regulatory point for protein trafficking in this pathway is the trans-Golgi network (TGN). At the TGN, vacuolar proteins are sorted from secreted proteins and packaged into vesicles for transport into the vacuole. Arabidopsis syntaxin 41 (SYP41) is a protein that resides in the TGN and shows sequence similarity to vesicle trafficking proteins. Immunoprecipitation of SYP41 co-precipitated a protein (named p65) found to be homologous to sorting nexins. Sorting nexins play a role in vesicular trafficking and contain a PX domain, that binds phosphoinositol lipids, and one or more coiled-coil regions for protein-protein interactions. The p65 protein may play a role in vesicle transport to the vacuole. Antibodies were raised against recombinant p65 protein, and the p65 protein was found to be distributed throughout the plant. A GFP-p65 fusion protein was transiently expressed in Arabidopsis protoplast and motile punctate spots were observed in the cytoplasm. We are now studying the specific localization and function of p65 in vesicle trafficking.