National Science Foundation
Research Grant 0542244
4/21/2006 - 5/22/2007
PI:  Andrea Doseff
Regulation of Apoptosis by the Interaction of Casp-3 with PKC and Small Heat Shock Proteins

ABSTRACT
Apoptosis or programmed cell death plays an essential role in normal development and provides a mechanism of cellular defense against pathogens and oncogenic factors in multicellular organisms. In animal cells, apoptosis is performed by a group of conserved cysteine proteases, named caspases. Understanding the mechanisms by which caspase activity is turned on and off poses a fundamental question in biology today. Protein Kinase Cd (PKCd) and the small heat shock protein 27 (hsp27) interact with caspase-3. PKCd phosphorylates caspase-3 enhancing its activity and preliminary results suggested that hsp27 inhibits caspase-3 activity. Moreover, the subcellular localization of hsp27 changes during caspase-3 activation in a PKCd-dependent fashion. This project will study the hypothesis that the ternary caspase-3:PKCd:hsp27 and/or a dimeric casp-3:hasp27 complexes play a key role in the regulation of caspase-3 activity. These experiments will establish first the mechanism by which hsp27 inhibits caspase-3 activity. Studies will focus on exploring whether hsp27 inhibits the proteolytic processing leading to the activation of caspase-3 or its protease activity. Next, this project will determine whether the phosphorylation of hsp27 by PKCd affects the inhibitory activity of hsp27. Second, the studies will examine the formation of the ternary and dimeric complexes and how the PKCd activity affects the distribution and association of these proteins in vivo. Together, these studies will provide crucial information on the basic mechanisms by which posttranslational modifications and protein-protein interactions control a process essential to the life and death of cells in multicellular organisms. Dr. Doseff has trained several undergraduate students some of whom are underrepresented minorities. Some of these students have presented their research results in international meetings as well as co-authored several publications. Through this project, Dr. Doseff will be able to involve several underrepresented minority students in various aspects of the study and will continue to participate in the university's effort to attract underrepresented minority students in the sciences.