Patrick L. Williamson

Professor of Biological Sciences, Amherst College

P. Williamson Biology Dept Website

Ph.D.: Harvard University
Postdoctoral Training: National Institutes of Health

Lipid Asymmetry in the Plasma Membrane

We study the mechanisms which determine the distribution of the various types of lipids between the two leaflets of the plasma membrane lipid bilayer, and the cell functions which depend on the resulting distributions. In the study of mechanisms, we are cloning the protein which generates the normal asymmetric lipid distribution, and attempting to identify the protein that rearranges that distribution. In the study of functions, we have been led to studies of lymphocyte differentiation and death, and the development and aging of red cells. In the course of the experiments, we use techniques of molecular biology (cloning and sequencing), cell biology (microscopy and fluorescent cell analysis), and biochemistry (enzyme assay and purification).

Representative publications:

Westerman, MP, D Green, A Gilman-Sachs, K Beaman, S Freels, L Boggio, S Allen, L Zuckerman, R Schlegel, and P Williamson(2002), Coagulation changes in Individuals with Sickle Cell Trait,Amer J Hematol , 69: 89-94

Williamson, P., S van den Eijnde and RA Schlegel (2001), Phosphatidylserine exposure and phagocytosis of apoptotic cells, In Apoptosis, a volume of Methods in Cell Biology (L. Schwartz and J. Ashwell, eds), Academic Press, San Diego, CA. 66: 339-365

Williamson, P. and RA Schlegel (2001), Of umbrellas, jazz and slow-steppin', Cell Death Different 8:104-105 (2001)

Schlegel, RA. and Patrick Williamson (2001), Phosphatidylserine, a Death Knell, Cell Death Different 8: 551-563

Williamson, P., A Christie, T Kohlin, RA Schlegel, P Comfurius, M Harmsma, RFA Zwaal, and EM Bevers, Phospholipid Scramblase (2001), Activation Pathways in Lymphocytes Biochemistry 40: 8065-8072

Callahan, MK., P Williamson, and RA Schlegel (2000), Surface Expression of Phosphatidylserine on Macrophages is Required for Phagocytosis of Apoptotic Thymocytes. Cell Death Different 7: 645-653

Schlegel, RA., MK. Callahan and P Williamson (2000), The Central Role of Phosphatidylserine in the Phagocytosis of Apoptotic Thymocytes, Ann NY Acad Sci 926: 217-225

Schlegel, RA., S Krahling, M K Callahan and P Williamson(1999), CD14 is a Component of Multiple Recognition Systems used by Macrophages to Phagocytose Apoptotic Lymphocytes. Cell Death Different 6: 583-592

Halleck, MS., JF Lawler, Jr., S Blackshaw, L Gao, P Nagarajan, C Hacker, S Pyle, JT Newman, Y Nakanishi, H Ando, D Weinstock, P Williamson, and RA Schlegel (1999), Differential Expression of Putative Transbilayer Amphipath Transporters. Physiol Genomics, 1: 139-150

Marguet, D., M-F Luciani, A Moynault, P Williamson, and G Chimini (1999), Engulfment of apoptotic cells involves the redistribution of membrane phosphatidylserine on phagocyte and prey. Nature Cell Biology 1: 454-6