Suzanne K. Murphy PhD
Suzanne K. Murphy PhD
Dean of Misher College of Arts & Sciences
Director of Pre_Health Professions Programs
Professor of Biology
Post-Doctoral Fellowship (SmithKline and French Laboratories Corp.Department of Tumor Biology )
Post-Doctoral Fellowship (Albert Einstein Medical Center Department of Pediatrics )
Analysis of early expression of the ras oncogene in NIH3T3 fibroblasts, specifically alterations in signal transduction pathways, control of cytoskeletal architecture and the role of heat shock proteins.
Osmotic change is an environmental stressor which can have significant effects on all cells from lower animals and to cells from mammals especially when they are found in areas of fluctuating osmotic conditions. Early work in our laboratory focused on the effects of high osmotic stress on the cytoskeleton of earthworm coelmocytes (leukocytes). Recently we have directed our research to studying mammalian cells normally subjected to significant changes in osmotic pressure. Circulating blood cells and kidney cells naturally may be effected by widely changing osmotic conditions.
Hypertonic stress and filopodia
We have shown that acute osmotic stress can greatly influence the cytoskeleton and consequently cell shape in earthworm coelomocytes and human hematopoietic (KG1a) cells. Under high osmotic conditions coelomocytes and KG1a cells both produce actin based filopodia. Effects of osmotic stress on cells is also reflected in the induction of heat shock proteins. Compared to levels of HSP 70 in KG1a cells in isotonic (255 mOsm) conditions, we have found that HSP 70 is increased significantly in the same cells following acute exposure to hypertonic (740 mOsm) conditions.
Osmotic stress and the cytoskeleton
Epithelial cells from the cortical and medullary regions of the mammalian kidney are naturally subjected to very different osmotic conditions in the two distinctive areas of the kidney. Since kidney cells are found in tissues and are not circulating, it is not surprising that while we find high osmotic pressure has significant effect on the cytoskeleton, no obvious cell shape change is observed. The kidney cell lines also tolerate acute osmotic stress at 830mOsm but have a dramatic reversible reorganization of their cytoskeletal in those conditions. We are now testing to determine whether HSP 70 is also involved in the adaptation of kidney cells.
Future studies are directed toward determining the relationship between cytoskeletal changes and protein kinase C, p38 kinase and heat shock proteins in cells naturally exposed to osmotically stressful conditions.
Selected Scholarly Activity
(* indicates undergraduate student)
(** indicates graduate student)
P. Patel, H. Tyagi, A. Khanna, M. Kasschau and S. Murphy. “Role of P38MAPK and heat shock proteins, HSP27 and HSP70, in Osmotic Stress in Renal vs. Blood Cells: A Comparative Study.” Molecular Biology of the Cell,19, 0361 (2008).
P. Patel, M. Dutt, M.R. Kasschau and S.K. Murphy. “Effect of P38MAPK on Filopodial Formation in KGla Human Hemotopoietic Cell Line.” Molecular Biology of the Cell, 18, 169 (2007).
Formation in a Human Hematopoietic Cell Line under Hypertonic Stress.” Molecular Biology of the Cell, 17, 2361 (2006)
A. Khanna, M.R. Kasschau and S.K. Murphy. “Cytoskeletal Reorganization in a Kidney Cell Line (LLC-PK1) under Hypertonic Stress.” Molecular Biology of the Cell, 17, 2361 (2006).
P. Patel, H. Tyagi, A. Khanna, M. Kasschau and S. Murphy. “Role of P38MAPK and heat shock proteins, HSP27 and HSP70, in Osmotic Stress in Renal vs. Blood Cells: A Comparative Study.” Molecular Biology of the Cell (2008).
M.D. Dutt, M.R. Kasschau and S.K. Murphy. “Filopodia formation in the KG1a human hematopoietic cell lineand earthworm coelomocytes under hypertonic osmotic stress.”Molecular Biology of the Cell, submitted (2005).
C. E. O’Brien and S.K. Murphy. “Interaction between PKC and HSP 70 in Fibroblasts overexpressing cellular Ras.” Molecular Biology of the Cell, submitted (2005).
C. O’Brien*, D. Lakic* and S.K. Murphy. “HSP70 levels are elevated in fibroblasts overexpressing cellular Ras protein.” Molecular Biology of the Cell, 15:361a (2004).
M. Braun*, W. Ding* and S.K. Murphy. “Regulatory interactions of PIP2-PLC, PC-PLD and PKC in cultured mouse fibroblasts.” Molecular Biology of the Cell, 14:147a (2003).
S.K. Murphy, R. Kareem*, Y.Lai* and J. Worobiej*. “Effects of overexpression of cellular ras vs. mutated ras.” Molecular Biology of the Cell 11:242a (2000).
W.Ding*, Y. Kwok* and S.K. Murphy. “Reciprocal regulations of PI-PLC and PC-PLC/PLD in ras transformed fibroblasts.” Molecular Biology of the Cell 9:117a (1998).
S.A. Morine*, S.K. Murphy and M.R. Kasschau. Cytoskeletal changes in coelomocytes from the earthworm, Lumbricus Terrestris, stimulated to adhere to immobilized protein matrices. Molecular Biology of the Cell, 8:270a, (1997).
T.T. Ho*, T.M. Allen* and S.K. Murphy. Ras p21 regulates phospholipase D through the cAMP cascade. Molecular Biology of the Cell, 8:142a, (1997).
T. Ho* and S.K. Murphy. Regulation of phospholipase C and D by RAS p21 and Protein kinase C. Molecular Biology of the Cell, 7:343a (1996).
S.K. Murphy, S. Robb-Gaspers* and A.M. Haines*. Protein kinase C regulates the activity of phospholipase C and phospholipase D in ras-expressing and non-ras-expressing NIH3T3 cells. Proceedings of the American Association for Cancer Research, 36:53 (1995).
Memberships in Professional Organizations
American Society for Cell Biology
American Association for the Advancement of Science
National Association of Advisors for the Health Professions
(member Board of Directors 2000-2002, Secretary 2002-present)
Northeast Association of Advisors for the Health Professions
(member of Executive Board 1996-2000, President 2000-2001)
Association for Women in Science
Association for Women in Cancer Research
|Office location:||Griffith Hall Room 212C|
|Mailing address:||Box 112|
University of Sciences
600 South 43rd Street
Philadelphia, PA 19104-4495
s [dot] murphy [at] usciences [dot] edu