The overall direction of the Molecular Mechanisms of Tumor Promotion Section is to elucidate the mechanisms of action of the phorbol esters and their endogenous analog, the lipophilic second messenger sn-1,2- diacylglycerol. Protein kinase C (PKC) is the major receptor for these compounds, and our emphasis is correspondingly directed at this family of isozymes. In a collaborative effort, we seek to combine mutational analysis with computer modeling and chemical synthesis to probe ligand - PKC interactions. Reflecting our developing insights, we are now able to make synthetic ligands approaching an affinity of 1 nM. A related issue is the significance of twin phorbol ester binding domains in typical PKCs. By mutating the individual binding domains, we find that the pattern of interaction of ligands with PKC depends both on the specific isotype and on the specific ligand. Our long term objective is to exploit such isotype differences to dissect subpathways of PKC mediated signal transduction. An on-going effort is directed at understanding the distinct biological roles of specific isoforms and the structural basis for their specificity. Using chimeric constructs, we find that both the regulatory and catalytic domains contribute to their specificity of action. The bryostatins, although activators of PKC in vitro, function as partial antagonists in intact cells. Protection of PKC delta from down regulation represents one mechanism contributing to bryostatin's unique activity. This resistance to down regulation in the presence of bryostatin resides in the catalytic domain of PKC delta. The phorbol-related diterpene resiniferatoxin acts as an ultrapotent analog of capsaicin and has permitted characterization of specific capsaicin receptors. We are now able to define distinct receptor subclasses with distinct functions. It had been believed that these receptors were found exclusively on sensory neurons. We have now demonstrated that the C-type vanilloid receptors are also found on other cell types, including mast cells, keratinocytes, and glial cells. These findings have important implications for the therapeutic development of vanilloids in the treatment of pain.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Intramural Research (Z01)
Project #
1Z01BC005270-16
Application #
6160887
Study Section
Special Emphasis Panel (CCTP)
Project Start
Project End
Budget Start
Budget End
Support Year
16
Fiscal Year
1997
Total Cost
Indirect Cost
Name
National Cancer Institute Division of Basic Sciences
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Cooke, Mariana; Zhou, Xiaoling; Casado-Medrano, Victoria et al. (2018) Characterization of AJH-836, a diacylglycerol-lactone with selectivity for novel PKC isozymes. J Biol Chem 293:8330-8341
Das, Joydip; Kedei, Noemi; Kelsey, Jessica S et al. (2018) Critical Role of Trp-588 of Presynaptic Munc13-1 for Ligand Binding and Membrane Translocation. Biochemistry 57:732-741
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Elhalem, Eleonora; Donadío, Lucía Gandolfi; Zhou, Xiaoling et al. (2017) Exploring the influence of indololactone structure on selectivity for binding to the C1 domains of PKC?, PKC?, and RasGRP. Bioorg Med Chem 25:2971-2980
Czikora, Agnes; Kedei, Noemi; Kalish, Heather et al. (2017) Importance of the REM (Ras exchange) domain for membrane interactions by RasGRP3. Biochim Biophys Acta Biomembr 1859:2350-2360
Ketcham, John M; Volchkov, Ivan; Chen, Te-Yu et al. (2016) Evaluation of Chromane-Based Bryostatin Analogues Prepared via Hydrogen-Mediated C-C Bond Formation: Potency Does Not Confer Bryostatin-like Biology. J Am Chem Soc 138:13415-13423
Czikora, Agnes; Lundberg, Daniel J; Abramovitz, Adelle et al. (2016) Structural Basis for the Failure of the C1 Domain of Ras Guanine Nucleotide Releasing Protein 2 (RasGRP2) to Bind Phorbol Ester with High Affinity. J Biol Chem 291:11133-47
Feng, Zhiwei; Pearce, Larry V; Zhang, Yu et al. (2016) Multi-Functional Diarylurea Small Molecule Inhibitors of TRPV1 with Therapeutic Potential for Neuroinflammation. AAPS J 18:898-913
Zhang, Feng; Hanson, Sonya M; Jara-Oseguera, Andres et al. (2016) Engineering vanilloid-sensitivity into the rat TRPV2 channel. Elife 5:
Petersen, Mark E; Kedei, Noemi; Lewin, Nancy E et al. (2016) Replacement of the Bryostatin A- and B-Pyran Rings With Phenyl Rings Leads to Loss of High Affinity Binding With PKC. Tetrahedron Lett 57:4749-4753

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