Inositol-1,3,4,5-tetrakisphosphate binding sites in control and ras-transformed NIH/3T3 fibroblasts

Megumi Taketo, Shigeru Yokoyama, Mitsunori Fukuda, Katsuhiko Mikoshiba, Haruhiro Higashida

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Inositol-1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4) binding properties were investigated in NIH/3T3 fibroblasts and its ras-transformant (DT cells), in which inositol tetrakisphosphates induce Ca2+ influx. [3H]Ins(1,3,4,5)P4 bound to membranes of both types of cells with Kd values of 10.6 and 8.6 nM, respectively. The rank order of inositol polyphosphates for displacing [3H]Ins(1,3,4,5)P4 in DT cells was Ins(1,3,4,5)P4 > inositol-1,3,4,5,6-pentakisphosphate > inositol hexakisphosphate > inositol-1,4,5-trisphosphate. This order is similar to that reported in two Ras-GTPase-activating proteins, GAP1(IP4BP) and GAP1m, which are also the Ins(1,3,4,S)P, binding proteins. Northern blot analysis revealed that NIH/3T3 and DT cells expressed mRNA species that were hybridizable with GAP1m cDNA. These results suggest that parental and ras-transformed NIH/3T3 fibroblasts possess GAP1-like proteins, which may be responsible for triggering inositol tetrakisphosphate-dependent Ca2 influx.

Original languageEnglish
Pages (from-to)349-352
Number of pages4
JournalBiochemical and biophysical research communications
Issue number1
Publication statusPublished - 1997 Oct 9
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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