The long-term objectives of the proposal are to understand both the physiological and molecular basis of the specificity which the fluorescent dye merocyanine 540 (MC540) displays for leukemia cells. The physiological basis of staining appears to involve the pathological retention by leukemia cells of an immature or activated phenotype of normal cells. The molecular basis of staining appears to reside in the lipid bilayer of the plasma membrane. This proposal is designed to investigate the mechanism controlling whether the bilayer is stained or not. MC540 preferentially intercalates into membranes whose lipids are loosely-packed. In erythrocytes, lipid packing is dependent on the transbilayer distribution of phospholipids, which in turn appears to be dependent on lipid-cytoskeletal interactions. Ghosts prepared from normal erythrocytes will be used as models to examine the role of protein modification in controlling these interactions. A photoactivable lipid analogue will be developed to determine whether these interactions are controlled by regulating the physical proximity of the spectrin cytoskeletal network to the membrane bilayer. The importance of plasma membrane lipid transport in altering transbilayer lipid distribution will be assessed. The results from these studies will be compared with results from similar experiments carried out with erythrocytes from patients with chronic myelogenous leukemia in order to determine the molecular basis for the staining of these simple leukemia cells. Finally, the role of these mechanisms in controlling the staining of activated and non-activated normal leukocytes will be evaluated as a first step in establishing the lesion in leukemic leukocytes responsible for their staining.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA028921-09
Application #
3168411
Study Section
Molecular Cytology Study Section (CTY)
Project Start
1981-07-01
Project End
1991-05-31
Budget Start
1989-06-01
Budget End
1990-05-31
Support Year
9
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Pennsylvania State University
Department
Type
Schools of Arts and Sciences
DUNS #
City
University Park
State
PA
Country
United States
Zip Code
16802
Verhoven, B; Schlegel, R A; Williamson, P (1992) Rapid loss and restoration of lipid asymmetry by different pathways in resealed erythrocyte ghosts. Biochim Biophys Acta 1104:15-23
Antia, R; Schlegel, R A; Williamson, P (1992) Binding of perforin to membranes is sensitive to lipid spacing and not headgroup. Immunol Lett 32:153-7
Williamson, P; Kulick, A; Zachowski, A et al. (1992) Ca2+ induces transbilayer redistribution of all major phospholipids in human erythrocytes. Biochemistry 31:6355-60
Pradhan, D; Williamson, P; Schlegel, R A (1991) Bilayer/cytoskeleton interactions in lipid-symmetric erythrocytes assessed by a photoactivable phospholipid analogue. Biochemistry 30:7754-8
Fujimagari, M; Williamson, P L; Schlegel, R A (1990) Ca2(+)-dependent membrane-binding proteins in normal erythrocytes and erythrocytes from patients with chronic myelogenous leukemia. Blood 75:1337-45
Williamson, P; Puchulu, E; Westerman, M et al. (1990) Erythrocyte membrane abnormalities in sickle cell disease. Biotechnol Appl Biochem 12:523-8
Pradhan, D; Weiser, M; Lumley-Sapanski, K et al. (1990) Peroxidation-induced perturbations of erythrocyte lipid organization. Biochim Biophys Acta 1023:398-404
Pradhan, D; Williamson, P; Schlegel, R A (1989) A photoactivable phospholipid analogue that specifically labels membrane cytoskeletal proteins of intact erythrocytes. Biochemistry 28:6943-9
Tullius, E K; Williamson, P; Schlegel, R A (1989) Effect of transbilayer phospholipid distribution on erythrocyte fusion. Biosci Rep 9:623-33
Del Buono, B J; White, S M; Williamson, P L et al. (1989) Plasma membrane lipid organization and the adherence of differentiating lymphocytes to macrophages. J Cell Physiol 138:61-9

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