HSP9O regulates cell survival via inositol hexakisphosphate kinase-2

Heat-shock proteins (HSPs) are abundant, inducible proteins best known for their ability to maintain the conformation of proteins and to refold damaged proteins. Some HSPs, especially HSP90, can be antiapoptotic and the targets of anticancer drugs. Inositol hexakisphosphate kinase-2 (IP6K2), one of...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2008-01, Vol.105 (4), p.1134
Main Authors: Chakraborty, Anutosh, Koldobskiy, Michael A, Sixt, Katherine M, Juluri, Krishna R, Mustafa, Asif K, Snowman, Adele M, Rossum, Damian B van, Patterson, Randen L, Snyder, Solomon H
Format: Article
Language:English
Subjects:
Apoptosis
Biochemistry
Cells
Chemotherapy
Kinases
Mutation
Proteins
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Summary:Heat-shock proteins (HSPs) are abundant, inducible proteins best known for their ability to maintain the conformation of proteins and to refold damaged proteins. Some HSPs, especially HSP90, can be antiapoptotic and the targets of anticancer drugs. Inositol hexakisphosphate kinase-2 (IP6K2), one of a family of enzymes generating the inositol pyrophosphate IP7 [diphosphoinositol pentakisphosphate (5-PP-IP5)], mediates apoptosis. Increased IP6K2 activity sensitizes cancer cells to stressors, whereas its depletion blocks cell death. We now show that HSP90 physiologically binds IP6K2 and inhibits its catalytic activity. Drugs and selective mutations that abolish HSP90-IP6K2 binding elicit activation of IP6K2, leading to cell death. Thus, the prosurvival actions of HSP90 reflect the inhibition of IP6K2, suggesting that selectively blocking this interaction could provide effective and safer modes of chemotherapy. [PUBLICATION ABSTRACT]
ISSN:0027-8424
1091-6490