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Comparison of VILIP-1 and VILIP-3 binding to phospholipid monolayers.

Rebaud S, Simon A, Wang CK, Mason L, Blum L, Hofmann A, Girard-Egrot A - PLoS ONE (2014)

Bottom Line: The neuronal calcium sensor proteins Visinin-like Proteins 1 (VILIP-1) and 3 (VILIP-3) are effectors of guanylyl cyclase and acetyl choline receptors, and transduce calcium signals in the brain.In the present study, we investigated the effect of membrane composition and solvent conditions on the membrane binding mechanisms of both VILIPs using lipid monolayers at the air/buffer interface.The extrusion of the conjugated myristoyl group, and the subsequent anchoring in the membrane constitutes the second stage of the binding mechanism, and ensures the sustained membrane-bound form of these proteins.

View Article: PubMed Central - PubMed

Affiliation: Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, Université Lyon 1, University of Lyon, ICBMS, CNRS UMR 5246, Bât. Curien, 43 bd du 11 Nov. 1918, F-69622 Villeurbanne cedex, France.

ABSTRACT
The neuronal calcium sensor proteins Visinin-like Proteins 1 (VILIP-1) and 3 (VILIP-3) are effectors of guanylyl cyclase and acetyl choline receptors, and transduce calcium signals in the brain. The "calcium-myristoyl" switch, which involves a post-translationally added myristoyl moiety and calcium binding, is thought to regulate their membrane binding capacity and therefore, play a critical role in their mechanism of action. In the present study, we investigated the effect of membrane composition and solvent conditions on the membrane binding mechanisms of both VILIPs using lipid monolayers at the air/buffer interface. Results based on comparison of the adsorption kinetics of the myristoylated and non-myristoylated proteins confirm the pivotal role of calcium and the exposed myristol moiety for sustaining the membrane-bound state of both VILIPs. However, we also observed binding of both VILIP proteins in the absence of calcium and/or myristoyl conjugation. We propose a two-stage membrane binding mechanism for VILIP-1 and VILIP-3 whereby the proteins are initially attracted to the membrane surface by electrostatic interactions and possibly by specific interactions with highly negatively charged lipids head groups. The extrusion of the conjugated myristoyl group, and the subsequent anchoring in the membrane constitutes the second stage of the binding mechanism, and ensures the sustained membrane-bound form of these proteins.

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Related in: MedlinePlus

Adsorption kinetics of VILIPs.Histograms of relative kinetics of binding of myristoylated and non-myristoylated VILIPs interaction to DOPS/DOPC (1:3) monolayers in the presence of calcium relative to those in the absence of calcium. Color coding: myr-VILIP-1 (blue), VILIP-1 (red), myr-VILIP-3 (green), and VILIP-3 (purple).
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pone-0093948-g003: Adsorption kinetics of VILIPs.Histograms of relative kinetics of binding of myristoylated and non-myristoylated VILIPs interaction to DOPS/DOPC (1:3) monolayers in the presence of calcium relative to those in the absence of calcium. Color coding: myr-VILIP-1 (blue), VILIP-1 (red), myr-VILIP-3 (green), and VILIP-3 (purple).

Mentions: Figure 3 compares the rate constants from binding kinetics of VILIPs in the presence of calcium ions relative to those in the presence of EDTA calculated for myristoylated and non-myristoylated VILIPs. The adsorption is faster for myr-VILIP-1 and myr-VILIP-3 than for non-myristoylated forms. These results clearly demonstrate the importance of the myristoyl group and the calcium ions in buffer as a temporal signal of myr-VILIPs binding. Whereas other factors (e.g. electrostatic interactions) contribute to binding of these proteins to membranes, these results highlight the role of the calcium-myristoyl switch for the kinetics of VILIP-membrane binding.


Comparison of VILIP-1 and VILIP-3 binding to phospholipid monolayers.

Rebaud S, Simon A, Wang CK, Mason L, Blum L, Hofmann A, Girard-Egrot A - PLoS ONE (2014)

Adsorption kinetics of VILIPs.Histograms of relative kinetics of binding of myristoylated and non-myristoylated VILIPs interaction to DOPS/DOPC (1:3) monolayers in the presence of calcium relative to those in the absence of calcium. Color coding: myr-VILIP-1 (blue), VILIP-1 (red), myr-VILIP-3 (green), and VILIP-3 (purple).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3974848&req=5

pone-0093948-g003: Adsorption kinetics of VILIPs.Histograms of relative kinetics of binding of myristoylated and non-myristoylated VILIPs interaction to DOPS/DOPC (1:3) monolayers in the presence of calcium relative to those in the absence of calcium. Color coding: myr-VILIP-1 (blue), VILIP-1 (red), myr-VILIP-3 (green), and VILIP-3 (purple).
Mentions: Figure 3 compares the rate constants from binding kinetics of VILIPs in the presence of calcium ions relative to those in the presence of EDTA calculated for myristoylated and non-myristoylated VILIPs. The adsorption is faster for myr-VILIP-1 and myr-VILIP-3 than for non-myristoylated forms. These results clearly demonstrate the importance of the myristoyl group and the calcium ions in buffer as a temporal signal of myr-VILIPs binding. Whereas other factors (e.g. electrostatic interactions) contribute to binding of these proteins to membranes, these results highlight the role of the calcium-myristoyl switch for the kinetics of VILIP-membrane binding.

Bottom Line: The neuronal calcium sensor proteins Visinin-like Proteins 1 (VILIP-1) and 3 (VILIP-3) are effectors of guanylyl cyclase and acetyl choline receptors, and transduce calcium signals in the brain.In the present study, we investigated the effect of membrane composition and solvent conditions on the membrane binding mechanisms of both VILIPs using lipid monolayers at the air/buffer interface.The extrusion of the conjugated myristoyl group, and the subsequent anchoring in the membrane constitutes the second stage of the binding mechanism, and ensures the sustained membrane-bound form of these proteins.

View Article: PubMed Central - PubMed

Affiliation: Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, Université Lyon 1, University of Lyon, ICBMS, CNRS UMR 5246, Bât. Curien, 43 bd du 11 Nov. 1918, F-69622 Villeurbanne cedex, France.

ABSTRACT
The neuronal calcium sensor proteins Visinin-like Proteins 1 (VILIP-1) and 3 (VILIP-3) are effectors of guanylyl cyclase and acetyl choline receptors, and transduce calcium signals in the brain. The "calcium-myristoyl" switch, which involves a post-translationally added myristoyl moiety and calcium binding, is thought to regulate their membrane binding capacity and therefore, play a critical role in their mechanism of action. In the present study, we investigated the effect of membrane composition and solvent conditions on the membrane binding mechanisms of both VILIPs using lipid monolayers at the air/buffer interface. Results based on comparison of the adsorption kinetics of the myristoylated and non-myristoylated proteins confirm the pivotal role of calcium and the exposed myristol moiety for sustaining the membrane-bound state of both VILIPs. However, we also observed binding of both VILIP proteins in the absence of calcium and/or myristoyl conjugation. We propose a two-stage membrane binding mechanism for VILIP-1 and VILIP-3 whereby the proteins are initially attracted to the membrane surface by electrostatic interactions and possibly by specific interactions with highly negatively charged lipids head groups. The extrusion of the conjugated myristoyl group, and the subsequent anchoring in the membrane constitutes the second stage of the binding mechanism, and ensures the sustained membrane-bound form of these proteins.

Show MeSH
Related in: MedlinePlus