TY - JOUR
T1 - Structure of a human inositol 1,4,5-trisphosphate 3-kinase
T2 - Substrate binding reveals why it is not a phosphoinositide 3-kinase
AU - González, Beatriz
AU - Schell, Michael J.
AU - Letcher, Andrew J.
AU - Veprintsev, Dmitry B.
AU - Irvine, Robin F.
AU - Williams, Roger L.
N1 - Funding Information:
We thank Olga Perisic for help with many aspects of the work and Alexey Murzin for useful discussions. We thank Joanne McCarthy, Ed Mitchell, and Andrew McCarthy for assistance with data collection at ESRF beamlines ID14-2, ID14-4, and ID29, respectively. B.G.P. was supported by a fellowship from Secretarı́a de Estado de Educación y Universidades and co-financed by the European Social Fund. The work was supported by the Wellcome Trust (R.F.I. and A.J.L.), the Royal Society (M.J.S. and R.F.I.), and the MRC (R.L.W.).
PY - 2004/9/10
Y1 - 2004/9/10
N2 - Mammalian cells produce a variety of inositol phosphates (InsPs), including Ins(1,4,5)P3 that serves both as a second messenger and as a substrate for inositol polyphosphate kinases (IPKs), which further phosphorylate it. We report the structure of an IPK, the human Ins(1,4,5)P3 3-kinase-A, both free and in complexes with substrates and products. This enzyme catalyzes transfer of a phosphate from ATP to the 3-OH of Ins(1,4,5)P 3, and its X-ray crystal structure provides a template for understanding a broad family of InsP kinases. The catalytic domain consists of three lobes. The N and C lobes bind ATP and resemble protein and lipid kinases, despite insignificant sequence similarity. The third lobe binds inositol phosphate and is a unique four-helix insertion in the C lobe. This lobe embraces all of the phosphates of Ins(1,4,5)P3 in a positively charged pocket, explaining the enzyme's substrate specificity and its inability to phosphorylate PtdIns(4,5)P2, the membrane-resident analog of Ins(1,4,5)P3.
AB - Mammalian cells produce a variety of inositol phosphates (InsPs), including Ins(1,4,5)P3 that serves both as a second messenger and as a substrate for inositol polyphosphate kinases (IPKs), which further phosphorylate it. We report the structure of an IPK, the human Ins(1,4,5)P3 3-kinase-A, both free and in complexes with substrates and products. This enzyme catalyzes transfer of a phosphate from ATP to the 3-OH of Ins(1,4,5)P 3, and its X-ray crystal structure provides a template for understanding a broad family of InsP kinases. The catalytic domain consists of three lobes. The N and C lobes bind ATP and resemble protein and lipid kinases, despite insignificant sequence similarity. The third lobe binds inositol phosphate and is a unique four-helix insertion in the C lobe. This lobe embraces all of the phosphates of Ins(1,4,5)P3 in a positively charged pocket, explaining the enzyme's substrate specificity and its inability to phosphorylate PtdIns(4,5)P2, the membrane-resident analog of Ins(1,4,5)P3.
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U2 - 10.1016/j.molcel.2004.08.004
DO - 10.1016/j.molcel.2004.08.004
M3 - Article
C2 - 15350214
AN - SCOPUS:4444223742
SN - 1097-2765
VL - 15
SP - 689
EP - 701
JO - Molecular cell
JF - Molecular cell
IS - 5
ER -