The intracellular contents of eukaryotic cells are sub-divided into discrete compartments, membrane enclosed organelles, which provide unique environments for specific cellular functions. Under special circumstances, such as during terminal differentiation of red blood cells and lens fiber cells or in programmed cell death, organelles are degraded. This critical process must be tightly regulated to insure that activation of the degradation process occurs at specific times and is directed towards distinct target membranes. Nevertheless, little is known about these critical aspects of this important cellular process. In this proposal we describe a comprehensive study of the mechanism by which organellar degradation occurs. Our studies will focus on the mechanism by which organellar degradation occurs. Our studies will focus on the cell biology and biochemistry of this degradative process during maturation of red blood cells. In our preliminary studies we have shown that 15-lipoxygenase (15-LOX) has the capability to both trigger and participate in organellar degradation that occurs during differentiation of red blood cells, by insertion into and permeabilization of target cellular membranes. This is followed by release and subsequent degradation of organellar contents. We further propose to study the mechanism for this action of 15 LOX on specific membranes, to define and isolate cellular factors involved in this degradation process. The in vivo significance of such factors will be examined by over-expressing or micro-injection of 15-LOX in murine erythroleukemia cells, a model for cell differentiation. These studies will enable us to determine whether over-expression of this enzyme is sufficient for differentiation of red cells. In addition, we will inject rabbits with known inhibitors of 15- LOX to ascertain whether this treatment alters organellar degradation and subsequent red cell differentiation.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL060889-04
Application #
6527177
Study Section
Molecular Cytology Study Section (CTY)
Program Officer
Thomas, John
Project Start
1999-08-01
Project End
2004-07-31
Budget Start
2002-08-01
Budget End
2004-07-31
Support Year
4
Fiscal Year
2002
Total Cost
$257,395
Indirect Cost
Name
Sloan-Kettering Institute for Cancer Research
Department
Type
DUNS #
064931884
City
New York
State
NY
Country
United States
Zip Code
10065
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Vijayvergiya, Chetan; De Angelis, Dino; Walther, Matthias et al. (2004) High-level expression of rabbit 15-lipoxygenase induces collapse of the mitochondrial pH gradient in cell culture. Biochemistry 43:15296-302
Walther, Matthias; Anton, Monika; Wiedmann, Martin et al. (2002) The N-terminal domain of the reticulocyte-type 15-lipoxygenase is not essential for enzymatic activity but contains determinants for membrane binding. J Biol Chem 277:27360-6
Hundley, Heather; Eisenman, Helene; Walter, William et al. (2002) The in vivo function of the ribosome-associated Hsp70, Ssz1, does not require its putative peptide-binding domain. Proc Natl Acad Sci U S A 99:4203-8
Grullich, C; Duvoisin, R M; Wiedmann, M et al. (2001) Inhibition of 15-lipoxygenase leads to delayed organelle degradation in the reticulocyte. FEBS Lett 489:51-4