Work

Role of lipid packing in the activity of phospholipase C-δ1 as determined by hydrostatic pressure measurements

Year: 1999

Type: article

Abstract: Previous studies with phospholipid monolayers revealed a large decrease in the activity of phosphoinositide-specific phospholipase C-δ1 (PLC-δ1) which catalyses the hydrolysis of PtdIns(4,5)P2 as lateral pressure is applied to the membrane. If stress on the membrane is the sole inhibitor of PLC-δ1 activity, the enzyme must penetrate the membrane surface to engage its substrate. To test the effect on PLC-δ1 activity of lipid packing in the absence of a directional stress, we examined the effects of increasing hydrostatic pressure on enzymic activity. We find that, in contrast with monolayer studies, increasing lipid packing by hydrostatic pressure does not affect membrane binding and increases enzymic activity by 90% in going from atmospheric pressure to 108 Pa (approx. 1000 atm). The increase in activity could be accounted for mainly by electrostriction of water around the multiply-charged product. Our results show that when there is no net stress on the monolayer, lipid packing does not alter PLC-δ1 activity, possibly because penetration of the enzyme into the membrane surface is shallow. We suggest that, in biological membranes, the activity of this and possibly other interfacial proteins is independent of headgroup packing.

Source: Biochemical Journal

DOI: 10.1042/0264-6021:3410571

Authors: Mario REBECCHI, Marjorie BONHOMME, Suzanne SCARLATA

Institutions: State University of New York, Stony Brook University

Language: English

Topic: Lipid Membrane Structure and Behavior

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: bronze

Funders: National Institutes of Health, National Institute of General Medical Sciences

Awards: G2986483745, G3261069961, Activation of Phospholipase Cbeta by G Proteins