Journal Article

Identification and Characterization of a Novel Human Phosphatidylinositol 4-kinase

Kazufumi Suzuki, Hisanobu Hirano, Keiichi Okutomi, Mikio Suzuki, Yoshiaki Kuga, Tsutomu Fujiwara, Naohide Kanemoto, Kaichi Isono and Masato Horie

in DNA Research

Published on behalf of Kazusa DNA Research Institute

Volume 4, issue 4, pages 273-280
Published in print January 1997 | ISSN: 1340-2838
Published online January 1997 | e-ISSN: 1756-1663 | DOI: http://dx.doi.org/10.1093/dnares/4.4.273

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The extensive sequence homology that exists among the catalytic domains of phosphatidylinositol 3- and 4-kinases allowed us to clone a novel human gene encoding a putative phosphatidylinositol kinase, NPIK. Among other known phosphatidylinositol 3- and 4-kinases, NPIK was most closely related to yeast PIK1 phosphatidylinositol 4-kinase. Several forms of NPIK cDNAs were isolated, and expression of NPIK message was detected in a wide variety of tissues. Fluorescence in situ hybridization and radiation hybrid analyses assigned the NPIK gene to human chromosome 1. Recombinant NPIK protein catalyzed a conversion from phosphatidylinositol to phosphatidylinositol 4-phosphate. The catalytic activity of NPIK was augmented by Triton X-100, and was reduced in the presence of adenosine. Using green .uorescent protein system we determined that NPIK is localized in the cytoplasm. Taken together, the data suggest that NPIK may play a pivotal role in regulating the synthesis of phosphatidylinositol 4-phosphate at the site(s) accessible from cytoplasm.

Keywords: phosphatidylinositol 4-kinase; cDNA sequence; human chromosome 1

Journal Article.  0 words. 

Subjects: Genetics and Genomics

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