4FRF

Structural Studies and Protein Engineering of Inositol Phosphate Multikinase

4FRF の概要

• エントリーDOI: 10.2210/pdb4frf/pdb
• 分子名称: Inositol polyphosphate multikinase alpha, SULFATE ION (2 entities in total)
• 機能のキーワード: atp grasp, inositol phosphate kinase, transferase
• 由来する生物種: Arabidopsis thaliana (mouse-ear cress,thale-cress)
• 細胞内の位置: Nucleus : Q9LY23
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 62089.07

構造登録者

Endo-Streeter, S.T.,Tsui, M.,Odom, A.R.,York, J.D. (登録日: 2012-06-26, 公開日: 2012-08-15, 最終更新日: 2024-02-28)

主引用文献

Endo-Streeter, S.,Tsui, M.K.,Odom, A.R.,Block, J.,York, J.D.
Structural studies and protein engineering of inositol phosphate multikinase.
J.Biol.Chem., 287:35360-35369, 2012

PubMed Abstract: Inositol phosphates (IPs) regulate vital processes in eukaryotes, and their production downstream of phospholipase C activation is controlled through a network of evolutionarily conserved kinases and phosphatases. Inositol phosphate multikinase (IPMK, also called Ipk2 and Arg82) accounts for phosphorylation of IP(3) to IP(5), as well as production of several other IP molecules. Here, we report the structure of Arabidopsis thaliana IPMKα at 2.9 Å and find it is similar to the yeast homolog Ipk2, despite 17% sequence identity, as well as the active site architecture of human IP(3) 3-kinase. Structural comparison and substrate modeling were used to identify a putative basis for IPMK selectivity. To test this model, we re-engineered binding site residues predicted to have restricted substrate specificity. Using steady-state kinetics and in vivo metabolic labeling studies in modified yeast strains, we observed that K117W and K117W:K121W mutants exhibited nearly normal 6-kinase function but harbored significantly reduced 3-kinase activity. These mutants complemented conditional nutritional growth defects observed in ipmk null yeast and, remarkably, suppressed lethality observed in ipmk null flies. Our data are consistent with the hypothesis that IPMK 6-kinase activity and production of Ins(1,4,5,6)P(4) are critical for cellular signaling. Overall, our studies provide new insights into the structure and function of IPMK and utilize a synthetic biological approach to redesign inositol phosphate signaling pathways.

PubMed: 22896696
DOI: 10.1074/jbc.M112.365031

実験手法

X-RAY DIFFRACTION (2.9 Å)