Mutation in the pleckstrin homology domain of the human phospholipase C-delta 1 gene is associated with loss of function.
The delta-type phospholipase C (PLC) is thought to be evolutionally the most basal form in the mammalian PLC family. One of the delta-type isoforms, PLC-delta 1, binds to both phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) and inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) with a high affinity via its pleckstrin homology (PH) domain. We report here a missense mutation in the region encoding the C-terminal PH domain of the human PLC-delta 1. This is also the first report of a mutation in the human PLC genes. A single base substitution (G to A) causes the amino acid replacement, Arg105 to His. Site-directed mutagenesis of the glutathione-S-transferase (GST)/PLC-delta 1 fusion protein changing Arg105 to His resulted in a fourfold decrease in the affinity of specific Ins(1,4,5)P3 binding and a reduction in PtdIns(4,5)P2 hydrolysing activity to about 40% of that of the wild-type enzyme. This remarkable loss of function can be interpreted in terms of a conformational change in the PH domain.
Shimohama
S
S
Department of Neurology, Faculty of Medicine, Kyoto University, Japan. i53367@sakura.kudpc.kyoto-u.ac.jp
Kamiya
S
S
Fujii
M
M
Ogawa
T
T
Kanamori
M
M
Kawamata
J
J
Imura
T
T
Taniguchi
T
T
Yagisawa
H
H
D001798:Blood Proteins / Q000235:genetics*; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics*; D007700:Kinetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism; D054803:Phospholipase C delta; D010750:Phosphoproteins; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D010738:Type C Phospholipases / Q000235:genetics*
D001798:Blood Proteins; D007527:Isoenzymes; D019269:Phosphatidylinositol 4,5-Diphosphate; D010750:Phosphoproteins; C039077:platelet protein P47; D015544:Inositol 1,4,5-Trisphosphate; D010738:Type C Phospholipases; D054803:Phospholipase C delta