H. (Johnny) Fares

Assistant Professor
Ph.D., University of North Carolina at Chapel Hill

Contact Information
Building: Life Sciences South
Room: 531
Phone: 626-3759
Email: fares@email.arizona.edu

Research Interests
The trafficking of vesicles/membrane between different compartments of a cell is an essential process in all eukaryotic cells and is used to maintain cellular integrity, to interact with the extracellular environment, and to generally modulate various cellular activities. Numerous advances have been made in understanding different pathways of vesicle trafficking and in elucidating some of the factors that regulate them; these advances have demonstrated a striking conservation of these pathways among all eukaryotic cells.

We have taken a genetic approach to study vesicle trafficking in the nematode C. elegans whose small size, ease of handling, and sequenced genome makes it perfectly suited for that purpose. We have concentrated on two separate pathways: 1) endocytosis of extracellular material by scavenger cells, and 2) polarized secretion by an epithelial cell sheet.

There are six cells called coelomocytes in the body cavity of C. elegans that constitutively endocytose fluid. We have established as assay whereupon GFP secreted into the body cavity is taken up by these cells and have identified several genes involved in this process. Future plans include studying the function of these genes in this process and identifying other genes using forward and reverse genetic approaches. The comparative analysis of endocytosis in C. elegans and in other systems should give us a better understanding of this central biological process.

The C. elegans hypodermis is a polarized epithelial layer with well defined apical and basolateral domains. We have shown that GFP secreted from these cells is targeted to the apical domain. We have used this assay to screen for mutants defective in this process and have identified some genes involved in this process. Future plans include the analysis of these genes and the identification of others that function in regulating the targeted delivery of vesicles. The aim is to better understand how epithelial cells establish and maintain their polarity.

Selected Publications
Fares, H., and I. Greenwald. 1999. SEL-5, a serine/threonine kinase that facilitates lin-12 activity in Caenorhabditis elegans. Genetics 153: 1641-1654.

Fares, H., and I. Greenwald. 2001. Regulation of endocytosis by CUP-5, the Caenorhabditis elegans mucolipin-1 homologue. Nature Genetics 28: 64-68.

Fares, H., and I. Greenwald. 2001. Genetic analysis of endocytosis in Caenorhabditis elegans: coelomocyte uptake defective mutants. Genetics 159: 133-145.

Fares, H., and B. Grant. 2002. Deciphering endocytosis in Caenorhabditis elegans. Traffic 3:11-19.