How versatile are inositol phosphate kinases?
This review assesses the extent and the significance of catalytic versatility shown by several inositol phosphate kinases: the inositol phosphate multikinase, the reversible Ins(1,3,4) P (3)/Ins(3,4,5,6) P (4) kinase, and the kinases that synthesize diphosphoinositol polyphosphates. Particular emphasis is placed upon data that are relevant to the situation in vivo. It will be shown that catalytic promiscuity towards different inositol phosphates is not typically an evolutionary compromise, but instead is sometimes exploited to facilitate tight regulation of physiological processes. This multifunctionality can add to the complexity with which inositol signalling pathways interact. This review also assesses some proposed additional functions for the catalytic domains, including transcriptional regulation, protein kinase activity and control by molecular 'switching', all in the context of growing interest in 'moonlighting' (gene-sharing) proteins.
Inositol Signaling Section, Laboratory of Signal Transduction, NIEHS/NIH/DHSS Research Triangle Park, NC 27709, USA. shears@niehs.nih.gov
Stephen B
SB
Shears
D000818:Animals; D020134:Catalytic Domain; D006801:Humans; D007295:Inositol Phosphates / Q000737:chemistry / Q000378:metabolism*; D008956:Models, Chemical; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry* / Q000378:metabolism* / Q000502:physiology; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity
D007295:Inositol Phosphates; D017853:Phosphotransferases (Alcohol Group Acceptor)