Regulation of nuclear processes by inositol polyphosphates.
Inositide signaling pathways represent a multifaceted ensemble of cellular switches capable of regulating a number of processes, for example, intracellular calcium release, membrane trafficking, chemotaxis, ion channel activity and several nuclear functions. Over 30 inositide messengers are found in eukaryotic cells that may be grouped into two classes: (1) inositol lipids, phosphatidylinositols or phosphoinositides (PIPs) and (2) water-soluble inositol polyphosphates (IPs). This review will focus on inositol polyphosphate kinases (IPK) and inositol pyrophosphate synthases (IPS) responsible for the cellular production of IP(4), IP(5) IP(6) and PP-IPs. Of interest, IPK and IPS proteins localize, in part, within the nucleus and their activities are necessary for proper regulation of gene expression, mRNA export, DNA repair and telomere maintenance. The breadth of nuclear processes regulated and the evolutionary conservation of the genes involved in their synthesis have sparked renewed interest in inositide messengers derived from sequential phosphorylation of inositol 1,4,5-trisphosphate.
York
John D
JD
Departments of Pharmacology and Cancer Biology and of Biochemistry, Howard Hughes Medical Institute, Duke University Medical Center, Box 3813, Durham, NC 27710, USA. yorkj@duke.edu
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D002468:Cell Physiological Phenomena; D005246:Feedback / Q000502:physiology; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism*; D009685:Nuclear Envelope / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
D007295:Inositol Phosphates; D018129:Phosphatidylinositol Phosphates; D017853:Phosphotransferases (Alcohol Group Acceptor)