Graduate Faculty Directory
Margaret Kasschau
Department of Biological Sciences
Education
- BA (Rochester)
- MS, PhD (South Carolina)
Faculty Appointments
Professor of Biology
Research Interest
Hypertonic stress and filopodia
Osmotic stress and the cytoskeletion
Molecular approaches
Synopsis
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 cytoskeletion
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.
Molecular approaches
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.
Publications & Presentations
- "Formation of filopodia in earthworm (Lumbricus terrestris) coelomocytes in response to osmotic stress.", Kasschau MR, Ngo TD, Sperber LM, and Tran KL. Zoology, 2007, in press
- "Cytoskeletal reorganization in a kidney cell line (LLC-PK1) under osmotic stress.", Khanna AS, Murphy SK, and Kasschau MR. Molecular Biology of the Cell, 2006, in press
- "Role of HSP 70 and the cytoskeleton in podial formation in a human hematopoietic cell line under hypertonic stress.", Dutt MD, Kasschau MR, and Murphy SK. Molecular Biology of the Cell, 2006, in press
- "Filopodia formation in the KG1a human hematopoietic cell line and earthworm coelomocytes under hypertonic conditions.", Dutt MD, Kasschau MR, and Murphy SK. Molecular Biology of the Cell, 2005, 16:758a
- "Interaction between PKC and HSP 70 in fibroblasts overexpressing cellular Ras.", O'Brien C and Murphy SK. Molecular Biology of the Cell, 2005, 16:28a
Attachments
Contact Information
Office:
Whitecar Hall
Room # 2300
Box # 65
Phone: 215.596.7558
Email: m.kassch@usp.edu
