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Catalysis by phospholipase C delta1 requires that Ca2+ bind to the catalytic domain, but not the C2 domain.
Biochemistry. 1998 Apr 07; 37(14):5020-8.B

Abstract

The hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) by phosphoinositide-specific phospholipase C (PLC) is absolutely dependent on Ca2+. The PH domain truncated catalytic core of rat phospholipase C delta1 (PLC-delta1) has Ca2+ binding sites in its catalytic and C2 domains, and potential Ca2+ binding sites in two EF-hands. A catalytically inactive PLC-delta1 catalytic core bound with low affinity to PIP2-containing vesicles in the presence of Ca2+. A mutant PLC-delta1 has been engineered which lacks the C2 domain Ca2+ binding site and the surrounding loops known as the jaws. Isothermal calorimetric titration showed four Ca2+ ions bind to the wild-type PLC-delta1 catalytic core in solution but only one binds to the C2 domain jaws deletion mutant. The activity and Ca2+ dependence of wild-type and mutant phospholipase Cs were determined using substrate incorporated in detergent micelles and in large unilamellar vesicles. The activities of wild-type and mutant were identical to each other in both assay systems. Wild-type and the C2 jaws deletion mutant of PLC have Hill coefficients of 1.12-1.16 with respect to [Ca2+]. We conclude that a single Ca2+ bound to the catalytic domain is entirely responsible for the Ca2+ dependence of the basal activity of PLC-delta1.

Authors+Show Affiliations

Laboratory of Molecular Biology, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0580, USA.No affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

9538021

Citation

Grobler, J A., and J H. Hurley. "Catalysis By Phospholipase C Delta1 Requires That Ca2+ Bind to the Catalytic Domain, but Not the C2 Domain." Biochemistry, vol. 37, no. 14, 1998, pp. 5020-8.
Grobler JA, Hurley JH. Catalysis by phospholipase C delta1 requires that Ca2+ bind to the catalytic domain, but not the C2 domain. Biochemistry. 1998;37(14):5020-8.
Grobler, J. A., & Hurley, J. H. (1998). Catalysis by phospholipase C delta1 requires that Ca2+ bind to the catalytic domain, but not the C2 domain. Biochemistry, 37(14), 5020-8.
Grobler JA, Hurley JH. Catalysis By Phospholipase C Delta1 Requires That Ca2+ Bind to the Catalytic Domain, but Not the C2 Domain. Biochemistry. 1998 Apr 7;37(14):5020-8. PubMed PMID: 9538021.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Catalysis by phospholipase C delta1 requires that Ca2+ bind to the catalytic domain, but not the C2 domain. AU - Grobler,J A, AU - Hurley,J H, PY - 1998/5/16/pubmed PY - 1998/5/16/medline PY - 1998/5/16/entrez SP - 5020 EP - 8 JF - Biochemistry JO - Biochemistry VL - 37 IS - 14 N2 - The hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) by phosphoinositide-specific phospholipase C (PLC) is absolutely dependent on Ca2+. The PH domain truncated catalytic core of rat phospholipase C delta1 (PLC-delta1) has Ca2+ binding sites in its catalytic and C2 domains, and potential Ca2+ binding sites in two EF-hands. A catalytically inactive PLC-delta1 catalytic core bound with low affinity to PIP2-containing vesicles in the presence of Ca2+. A mutant PLC-delta1 has been engineered which lacks the C2 domain Ca2+ binding site and the surrounding loops known as the jaws. Isothermal calorimetric titration showed four Ca2+ ions bind to the wild-type PLC-delta1 catalytic core in solution but only one binds to the C2 domain jaws deletion mutant. The activity and Ca2+ dependence of wild-type and mutant phospholipase Cs were determined using substrate incorporated in detergent micelles and in large unilamellar vesicles. The activities of wild-type and mutant were identical to each other in both assay systems. Wild-type and the C2 jaws deletion mutant of PLC have Hill coefficients of 1.12-1.16 with respect to [Ca2+]. We conclude that a single Ca2+ bound to the catalytic domain is entirely responsible for the Ca2+ dependence of the basal activity of PLC-delta1. SN - 0006-2960 UR - https://www.unboundmedicine.com/medline/citation/9538021/Catalysis_by_phospholipase_C_delta1_requires_that_Ca2+_bind_to_the_catalytic_domain_but_not_the_C2_domain_ L2 - https://dx.doi.org/10.1021/bi972952w DB - PRIME DP - Unbound Medicine ER -