Functional expression and characterisation of a new human phosphatidylinositol 4-kinase PI4K230

Thor Gehrmann, Hülya Gülkan, Silke Suer, Friedrich W. Herberg, Andras Balla, György Vereb, Georg W. Mayr, Ludwig M.G. Heilmeyer

Research output: Article

26 Citations (Scopus)

Abstract

By constructing DNA probes we have identified and cloned a human PtdIns 4-kinase, PI4K230, corresponding to a mRNA of 7.0 kb. The cDNA encodes a protein of 2044 amino acids. The C-terminal part of ca. 260 amino acids represents the catalytic domain which is highly conserved in all recently cloned PtdIns 4-kinases. N-terminal motifs indicate multiple heterologous protein interactions. Human PtdIns 4-kinase PI4K230 expressed in vitro exhibits a specific activity of 58 μmol mg-1 min-1. The enzyme expressed in Sf9 cells is essentially not inhibited by adenosine, it shows a high K(m) for ATP of about 300 μM and it is half-maximally inactivated by approximately 200 nM wortmannin. These data classify this enzyme as type 3 PtdIns 4-kinase. Antibodies raised against the N-terminal part moderately activate and those raised against the C-terminal catalytic domain inhibit the enzymatic activity. The coexistence of two different type 3 PtdIns 4-kinases, PI4K92 and PI4K230, in several human tissues, including brain, suggests that these enzymes are involved in distinct basic cellular functions.

Original languageEnglish
Pages (from-to)341-356
Number of pages16
JournalBiochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
Volume1437
Issue number3
DOIs
Publication statusPublished - márc. 25 1999

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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