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Regulation of PLCβ2 by the electrostatic and mechanical properties of lipid bilayers.

Arduin A, Gaffney PR, Ces O - Sci Rep (2015)

Bottom Line: However, the regulatory mechanism of PLC is not yet understood in detail.Evidence was found for a direct interaction between PLC and the GTPases that mediate phospholipase activation.PLC activity was found to depend upon the electrostatic potential and the stored curvature elastic stress of the lipid membranes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Chemical Biology, Department of Chemical Biology, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.

ABSTRACT
Phosphoinositide-specific phospholipase C (PLC) is an important family of enzymes constituting a junction between phosphoinositide lipid signaling and the trans-membrane signal transduction processes that are crucial to many living cells. However, the regulatory mechanism of PLC is not yet understood in detail. To address this issue, activity studies were carried out using lipid vesicles in a model system that was specifically designed to study protein-protein and lipid-protein interactions in concert. Evidence was found for a direct interaction between PLC and the GTPases that mediate phospholipase activation. Furthermore, for the first time, the relationships between PLC activity and substrate presentation in lipid vesicles of various sizes, as well as lipid composition and membrane mechanical properties, were analyzed. PLC activity was found to depend upon the electrostatic potential and the stored curvature elastic stress of the lipid membranes.

No MeSH data available.


Related in: MedlinePlus

Effect on PLCβ2 activity of curvature elastic stress.The bar chart shows the average activity measured in duplicate samples (± the s.e.m.). The lipid vesicles tested for each set of samples have the following lipid ratios: DOPE:DOPC 16:0 (columns 1 & 2), 12.8:2.8 (columns 3 & 4), 11.1:4.2 (columns 5 & 6), 8.0:7.0 (columns 7 & 8), 4.8:9.8 (columns 9 & 10) and 0:16 (columns 11 & 12) mol/mol, and then DOPC:DMPC 9.8:4.9 (columns 13 & 14), 7.0:8.1 (columns 15 & 16), 4.2:11.4 (columns 17 & 18) and 0:16 (columns 19 & 20) mol/mol. The proportion of PtdIns (4,5)P2 substrate in the vesicles was constant at (DOPE + DOPC + DMPC): PtdIns (4,5)P2/[3H]-PtdIns (4,5)P2 16:1 mol/mol. All other conditions are the same as for Fig. 2.
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f8: Effect on PLCβ2 activity of curvature elastic stress.The bar chart shows the average activity measured in duplicate samples (± the s.e.m.). The lipid vesicles tested for each set of samples have the following lipid ratios: DOPE:DOPC 16:0 (columns 1 & 2), 12.8:2.8 (columns 3 & 4), 11.1:4.2 (columns 5 & 6), 8.0:7.0 (columns 7 & 8), 4.8:9.8 (columns 9 & 10) and 0:16 (columns 11 & 12) mol/mol, and then DOPC:DMPC 9.8:4.9 (columns 13 & 14), 7.0:8.1 (columns 15 & 16), 4.2:11.4 (columns 17 & 18) and 0:16 (columns 19 & 20) mol/mol. The proportion of PtdIns (4,5)P2 substrate in the vesicles was constant at (DOPE + DOPC + DMPC): PtdIns (4,5)P2/[3H]-PtdIns (4,5)P2 16:1 mol/mol. All other conditions are the same as for Fig. 2.

Mentions: Upon interaction with GG-Rac2 the stimulation of PLCβ2 (2–803 AA) decreased with the fall in the proportion of PE and the corresponding rise in that of DOPC (from DOPE: PtdIns(4,5)P2/[3H]-PtdIns(4,5)P2 16:1 mol/mol, to DOPC: PtdIns(4,5)P2/[3H]-PtdIns(4,5)P2 16:1 mol/mol vesicles). The decrease of PLCβ2 stimulation was even more pronounced, and then disappeared, when the DOPC in the lipid vesicles was replaced by DMPC (Fig. 8). These data indicated that the lower the stored curvature elastic stress in the lipid vesicles, the lower the activity of PLC in the presence of GTPγS and GG-Rac2 (PLCβ2 stimulation).


Regulation of PLCβ2 by the electrostatic and mechanical properties of lipid bilayers.

Arduin A, Gaffney PR, Ces O - Sci Rep (2015)

Effect on PLCβ2 activity of curvature elastic stress.The bar chart shows the average activity measured in duplicate samples (± the s.e.m.). The lipid vesicles tested for each set of samples have the following lipid ratios: DOPE:DOPC 16:0 (columns 1 & 2), 12.8:2.8 (columns 3 & 4), 11.1:4.2 (columns 5 & 6), 8.0:7.0 (columns 7 & 8), 4.8:9.8 (columns 9 & 10) and 0:16 (columns 11 & 12) mol/mol, and then DOPC:DMPC 9.8:4.9 (columns 13 & 14), 7.0:8.1 (columns 15 & 16), 4.2:11.4 (columns 17 & 18) and 0:16 (columns 19 & 20) mol/mol. The proportion of PtdIns (4,5)P2 substrate in the vesicles was constant at (DOPE + DOPC + DMPC): PtdIns (4,5)P2/[3H]-PtdIns (4,5)P2 16:1 mol/mol. All other conditions are the same as for Fig. 2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525138&req=5

f8: Effect on PLCβ2 activity of curvature elastic stress.The bar chart shows the average activity measured in duplicate samples (± the s.e.m.). The lipid vesicles tested for each set of samples have the following lipid ratios: DOPE:DOPC 16:0 (columns 1 & 2), 12.8:2.8 (columns 3 & 4), 11.1:4.2 (columns 5 & 6), 8.0:7.0 (columns 7 & 8), 4.8:9.8 (columns 9 & 10) and 0:16 (columns 11 & 12) mol/mol, and then DOPC:DMPC 9.8:4.9 (columns 13 & 14), 7.0:8.1 (columns 15 & 16), 4.2:11.4 (columns 17 & 18) and 0:16 (columns 19 & 20) mol/mol. The proportion of PtdIns (4,5)P2 substrate in the vesicles was constant at (DOPE + DOPC + DMPC): PtdIns (4,5)P2/[3H]-PtdIns (4,5)P2 16:1 mol/mol. All other conditions are the same as for Fig. 2.
Mentions: Upon interaction with GG-Rac2 the stimulation of PLCβ2 (2–803 AA) decreased with the fall in the proportion of PE and the corresponding rise in that of DOPC (from DOPE: PtdIns(4,5)P2/[3H]-PtdIns(4,5)P2 16:1 mol/mol, to DOPC: PtdIns(4,5)P2/[3H]-PtdIns(4,5)P2 16:1 mol/mol vesicles). The decrease of PLCβ2 stimulation was even more pronounced, and then disappeared, when the DOPC in the lipid vesicles was replaced by DMPC (Fig. 8). These data indicated that the lower the stored curvature elastic stress in the lipid vesicles, the lower the activity of PLC in the presence of GTPγS and GG-Rac2 (PLCβ2 stimulation).

Bottom Line: However, the regulatory mechanism of PLC is not yet understood in detail.Evidence was found for a direct interaction between PLC and the GTPases that mediate phospholipase activation.PLC activity was found to depend upon the electrostatic potential and the stored curvature elastic stress of the lipid membranes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Chemical Biology, Department of Chemical Biology, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.

ABSTRACT
Phosphoinositide-specific phospholipase C (PLC) is an important family of enzymes constituting a junction between phosphoinositide lipid signaling and the trans-membrane signal transduction processes that are crucial to many living cells. However, the regulatory mechanism of PLC is not yet understood in detail. To address this issue, activity studies were carried out using lipid vesicles in a model system that was specifically designed to study protein-protein and lipid-protein interactions in concert. Evidence was found for a direct interaction between PLC and the GTPases that mediate phospholipase activation. Furthermore, for the first time, the relationships between PLC activity and substrate presentation in lipid vesicles of various sizes, as well as lipid composition and membrane mechanical properties, were analyzed. PLC activity was found to depend upon the electrostatic potential and the stored curvature elastic stress of the lipid membranes.

No MeSH data available.


Related in: MedlinePlus