TY - JOUR
T1 - Inositol-1,3,4,5-tetrakisphosphate binding sites in control and ras-transformed NIH/3T3 fibroblasts
AU - Taketo, Megumi
AU - Yokoyama, Shigeru
AU - Fukuda, Mitsunori
AU - Mikoshiba, Katsuhiko
AU - Higashida, Haruhiro
PY - 1997/10/9
Y1 - 1997/10/9
N2 - 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.
AB - 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.
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U2 - 10.1006/bbrc.1997.7332
DO - 10.1006/bbrc.1997.7332
M3 - Article
C2 - 9345323
AN - SCOPUS:0031561395
VL - 239
SP - 349
EP - 352
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 1
ER -