Position(s):
Assistant Professor, Dept. of Bioscience & Biotechnology

Office: 230 Stratton Hall

Phone: (215) 895-2526 (Office)
            (215) 895- (Lab)

Email: pmo24@drexel.edu

B.S. - Biology, College of William and Mary
Ph.D. - Molecular and Cellular Pathobiology, Wake Forest University
Postdoctoral fellow - Columbia University, College of Physicians and Surgeon

Courses Taught

UNIV101: Freshman Seminar
BIO306: Biochemistry I Laboratory
BIO311: Metabolism
BIO610: Biochemistry II

The research in my lab has focused on using Saccharomyces cerevisiae (baker's yeast) as a model system to study lipid metabolism.  Being able to easily manipulate its sequenced genome, vary culture conditions, and utilize a wide variety of genetic screens makes this a very pliable and powerful model system.  Since many of the enzymes that mediate the reactions involved in lipid metabolism in yeast have been shown to have human homologs, our findings provide precedents for both enzymatic mechanism and regulation in higher eukaryotes. 
Currently, we are focusing on understanding how yeast establish the acyl chain composition found in phospholipids.  Whether saturated or unsaturated fatty acids are incorporated into the two possible positions in phospholipids depends on many different reactions.  Two acyltransferase reactions mediate the incorporation of acyl chains into phospholipids during de novo synthesis (figure 1).   Each of these reactions is mediated by two enzymes.  Investigating the reason for this apparent redundancy is one of our projects.  Additionally, after phospholipids are synthesized they undergo a remodeling process where acyl chains are removed by phospholipases and replaced by acyltransferases.   If the phospholipases and acyltransferases have different substrate specificity regarding the length and degree of saturation of the acyl chains, then a net alteration of cellular phospholipid composition occurs.  An important discovery in this field was our recent identification of the main phospholipid remodeling acyltransferase in yeast (Lpt1).  This work appears in the October 19, 2007 edition of the Journal of Biological Chemistry.  The project's success was the result of a fruitful collaboration with investigators at the University of Toronto and hard work by two graduate students and two undergraduate students in my lab.  Identification of this enzyme has initiated projects designed to characterize the human homologs of Lpt1.

Graduate Students

current:
Shilpa Jain, Ph.D. candidate

past:
Ang Bian, M.S. (2006)
Kavitha Sompalli, M.S. (2007)