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Unmyristoylated MARCKS-related protein (MRP) binds to supported planar phosphatidylcholine membranes
O Michielin1, J J Ramsden, G Vergères
1Department of Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland.
Abstract:
We have recently shown that unmyristoylated MARCKS-related protein (MRP) does not bind to neutral phospholipid vesicles, unless negatively charged phospholipids are present. Similar behaviour has also been reported for MARCKS itself. Here we have compared the binding of MRP to neutral and negatively charged supported planar lipid bilayer membranes (SPLM) using two-mode waveguide spectroscopy. We find appreciable binding of unmyristoylated MRP to neutral SPLM. We propose that hydrophobic residues in the effector domain constitute an additional factor capable of mediating MRP-membrane interaction.
Insights
Unmyristoylated MARCKS-related protein (MRP) binds to neutral membranes, contrary to previous findings. Hydrophobic residues in its effector domain likely mediate this interaction, expanding our understanding of protein-lipid binding.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- The binding of MARCKS-related protein (MRP) to lipid membranes is crucial for its cellular functions.
- Previous studies indicated unmyristoylated MRP requires negatively charged phospholipids for membrane interaction.
- Similar binding properties were observed for the related MARCKS protein.
Purpose of the Study:
- To investigate the binding of unmyristoylated MRP to neutral and negatively charged supported planar lipid bilayer membranes (SPLM).
- To determine if hydrophobic interactions contribute to MRP-membrane binding.
- To re-evaluate the conditions required for MRP membrane association.
Main Methods:
- Utilized two-mode waveguide spectroscopy to quantify MRP binding to SPLM.
- Compared binding affinities to neutral and negatively charged SPLM.
- Analyzed the role of hydrophobic residues in the effector domain.
Main Results:
- Demonstrated significant binding of unmyristoylated MRP to neutral SPLM.
- Observed binding to negatively charged SPLM as well.
- Identified appreciable binding even without negatively charged phospholipids.
Conclusions:
- Unmyristoylated MRP can bind to neutral lipid membranes.
- Hydrophobic residues within the MRP effector domain are key mediators of membrane interaction.
- This finding suggests an additional mechanism for MRP-membrane association beyond electrostatic interactions.