Interaction of a pseudosubstrate peptide of protein kinase C and its myristoylated form with lipid vesicles: only the myristoylated form translocates into the lipid bilayer.
Lipopeptides derived from protein kinase C (PKC) pseudosubstrates have the ability to cross the plasma membrane in cells and modulate the activity of PKC in the cytoplasm. Myristoylation or palmitoylation appears to promote translocation across membranes, as the non-acylated peptides are membrane impermeant. We have investigated, by fluorescence spectroscopy, how myristoylation modulates the interaction of the PKC pseudosubstrate peptide KSIYRRGARRWRKL with lipid vesicles and translocation across the lipid bilayer. Our results indicate that myristoylated peptides are intimately associated with lipid vesicles and are not peripherally bound. When visualized under a microscope, myristoylation does appear to facilitate translocation across the lipid bilayer in multilamellar lipid vesicles. Translocation does not involve large-scale destabilization of the bilayer structure. Myristoylation promotes translocation into the hydrophobic interior of the lipid bilayer even when the non-acylated peptide has only weak affinity for membranes and is also only peripherally associated with lipid vesicles.
Harishchandran
Avaronnan
A
Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad-500 007, India.
Nagaraj
Ramakrishnan
R
D002462:Cell Membrane / Q000378:metabolism; D002850:Chromatography, Gel; D003593:Cytoplasm / Q000378:metabolism; D004058:Diffusion; D004305:Dose-Response Relationship, Drug; D031541:Fluorescence Resonance Energy Transfer; D007454:Iodides / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D019814:Myristic Acid / Q000737:chemistry*; D009227:Myristic Acids / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D011493:Protein Kinase C / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D013050:Spectrometry, Fluorescence; D013997:Time Factors; D014364:Tryptophan / Q000737:chemistry
D007454:Iodides; D008051:Lipid Bilayers; D008055:Lipids; D009227:Myristic Acids; D010455:Peptides; D019814:Myristic Acid; D014364:Tryptophan; D011493:Protein Kinase C