Harvard University, A.B. Biochem, 1981;
Harvard University, Ph.D. Biochem. & Mol. Biol., 1988;
UCSF, Postdoc Biochem. & Biophysics, 1988-1993
Our laboratory studies membrane traffic in the ciliate Tetrahymena thermophila. Ciliates emerged as an early branch during eukaryotic evolution, and are far more distantly related to humans, for example, than are most organisms being studied by cell biologists. Our interest in these cells stems from the fact that ciliates are unicellular and offer a host of experimental advantages, but at the same time are highly complex and maintain many cellular features that are usually associated with animal cells. For example, ciliates have a prominent pathway for regulated secretion of polypeptides via vesicles that resemble metazoan dense core granules. The mechanisms responsible for granule formation in mammalian cells, in which they have typically been studied, are still poorly understood. We use a combination of biochemical, cell biological and both forward and revere genetic approaches. Our recent results highlight the important contribution of endolysosomal pathways to granule formation in Tetrahymena, and have led us to re-examine conserved and novel mechanisms underlying post-trans Golgi organization in eukaryotic cells.