title: Tracking peptide-membrane interactions: insights from in situ coupled confocal-atomic force microscopy imaging of NAP-22 peptide insertion and assembly.
abstract: Elucidating the role that charged membrane proteins play in determining cell membrane structure and dynamics is an area of active study. We have applied in situ correlated atomic force and confocal microscopies to characterize the interaction of the NAP-22 peptide with model membranes prepared as supported planar bilayers containing both liquid-ordered and liquid-disordered domains. Our results demonstrated that the NAP-22 peptide interacts with membranes in a concentration-dependent manner, preferentially inserting into DOPC (ld) domains. While at low peptide concentrations, the NAP-22 peptide formed aggregate-like structures within the ld domains, at high peptide concentrations, it appeared to sequester cholesterol into the ld domains and recruited phosphatidyl-myo-inositol 4,5-bisphosphate by inducing a blending effect that homogenizes the phase-segregated domains into one liquid-ordered domain. This study describes a possible mechanism by which the NAP-22 peptide can affect neuronal morphology.
authors.affiliation: Department of Biochemistry, University of Toronto, 4 Taddle Creek Road, Toronto, Canada M5S 3G9.
authors.forename: James E
authors.initials: JE
authors.lastname: Shaw
authors.forename: Raquel F
authors.initials: RF
authors.lastname: Epand
authors.forename: Koneswaran
authors.initials: K
authors.lastname: Sinnathamby
authors.forename: Zaiguo
authors.initials: Z
authors.lastname: Li
authors.forename: Robert
authors.initials: R
authors.lastname: Bittman
authors.forename: Richard M
authors.initials: RM
authors.lastname: Epand
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Yip
mesh_terms: D000818:Animals; D001896:Boron Compounds / Q000378:metabolism; D001923:Brain Chemistry / Q000276:immunology; D002148:Calmodulin-Binding Proteins / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D003952:Diagnostic Imaging / Q000379:methods; D008051:Lipid Bilayers / Q000378:metabolism*; D008566:Membranes / Q000378:metabolism*; D018625:Microscopy, Atomic Force / Q000379:methods*; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000276:immunology / Q000378:metabolism; D011485:Protein Binding; D013552:Swine
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D002148:Calmodulin-Binding Proteins; D003598:Cytoskeletal Proteins; D008051:Lipid Bilayers; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; D010713:Phosphatidylcholines; C066853:Basp1 protein, rat; D017853:Phosphotransferases (Alcohol Group Acceptor); C068961:phosphatidylinositol 4,5-biphosphate kinase; C017251:1,2-oleoylphosphatidylcholine