Structural, Functional, and Clinical Aspects of Myelin Proteins

Epand, Richard M.

doi:10.1016/b978-0-12-470348-3.50014-8

Cited by 2 publications

(3 citation statements)

References 251 publications

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“…No binding of MBP to the Ole,GroPCho vesicles was observed at conditions where the protein binds extensively to and aggregates PtdSer vesicles. In this context, it should be noted that aggregation of small Ole,GroPCho unilamellar vesicles has been reported [3,13,271. Furthermore, Ole,GroPCho reduced the interaction of MBP with PtdSer bilayers (Fig.…”

Section: Discussionmentioning

confidence: 94%

“…3) further suggests that the interaction of MBP with the acidic lipid bilayer is not solely governed by a 1 : 1 electrostatic binding to PtdSer. For further stabilization it would appear that the protein engages in additional surface interactions [3,28,291 which, apparently, are eliminated by Ole,GroPCho. Whether these interactions are hydrophobic in nature, given that Ole2-GroPCho is a strongly hydrated phospholipid, remains to be determined.…”

Section: Discussionmentioning

confidence: 99%

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Interaction of myelin basic protein with artificial membranes

Beest

Hoekstra

1993

European Journal of Biochemistry

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The interaction of myelin basic protein (MBP) with large unilamellar vesicles, composed of phosphatidylserine (PtdSer), phosphatidylserine/phosphatidylcholine (PtdSer/Ole2GroPCho) and phosphatidylcholine/cholesterol (Ole2GroPCho/cholesterol) was examined. Binding of MBP to the bilayers as well as the kinetics of this process were determined by a resonance energy transfer procedure. The ability of the protein to aggregate the vesicles subsequently was monitored continuously by absorbance measurements. The interaction was further characterized by determining the ability of MBP to induce membrane perturbations, as reflected by release of aqueous vesicle contents, and lipid mixing. The results demonstrate that Ole2GroPCho inhibits, while PtdSer and cholesterol strongly facilitate MBP-induced membrane aggregation. Furthermore, binding of MBP to vesicles and the subsequent aggregation event are separate processes, i.e. the extent of binding does not necessarily reflect the aggregation susceptibility. Overall, aggregation appears to be the rate-limiting step. Interaction of MBP with PtdSer bilayers results in a limited degree of lipid mixing, which is accompanied by extensive release of vesicle contents. For all other compositions, no lipid mixing occurs, while cholesterol effectively prevents release of vesicle contents. pH-dependent experiments indicate distinct mechanisms to be operative in MBP-induced aggregation of PtdSer and Ole2GroPCho/cholesterol bilayers. At neutral pH, protein-protein interactions appear relevant, while at acidic pH intervesicular bridges, established by monomers that may cause aggregation of PtdSer vesicles, but not of Ole2GroPCho/cholesterol vesicles. The observation that divalent cations reverse MBP-induced vesicle aggregation may have physiological relevance.

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Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Interaction of myelin basic protein with artificial membranes

Beest

Hoekstra

1993

European Journal of Biochemistry

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“…Numerous MBP isomers and isoforms are created by different exon splicing and various posttranslational modifications with probably different roles in the myelin compaction process . It is generally accepted that at least two MBP isoforms act as intermembrane adhesion proteins; they help to form and stabilize the major dense lines by cross-linking the cytoplasmic membrane leaflets. − …”

Section: Introductionmentioning

confidence: 99%

Adsorption of Membrane-Associated Proteins to Lipid Bilayers Studied with an Atomic Force Microscope: Myelin Basic Protein and Cytochrome c

2000

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Atomic force microscopy was used to study the structure of two membrane-associated proteins adsorbed to various supported phospholipid bilayers in physiological buffer. The aim was (a) to develop a preparation for the investigation of membrane-associated proteins at high resolution under native conditions and (b) to obtain information about the factors that determine the adsorption process and the structure of adsorbed proteins. Therefore, solid-supported membranes were formed on mica by spontaneous vesicle adsorption and spreading. Once a homogeneous, pinhole-free bilayer was formed, solutions containing the proteins at appropriate concentrations were applied. The two positively charged proteins chosen were myelin basic protein (MBP), which plays an essential role in the formation of functional myelin, and cytochrome c. On charged bilayers, MBP applied at concentrations of 0.5-50 µg/mL formed aggregates of defined height (1.9 ( 0.2 nm on negatively and 2.7 ( 0.2 nm on positively charged lipids), which at high concentration covered the entire bilayer. These aggregates are probably monomolecular layers of MBP. On neutral lipid adsorbed MBP formed irregular aggregates. Cytochrome c showed a different adsorption: On negatively charged lipid it formed aggregates of defined, monomolecular height (3.3 ( 0.2 nm). On neutral bilayers small aggregates were observed. On positively charged lipid no adsorption was observed at all. These results indicate that (a) the adsorption of cytomchrome c can be interpreted in terms of a dominating electrostatic interaction; (b) MBP adsorption to lipid bilayers is not exclusively electrostatically driven and depends on the specific lipid bilayer composition; (c) the structure of adsorbed aggregates indicates a strong protein-protein interaction.

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Structural, Functional, and Clinical Aspects of Myelin Proteins

Cited by 2 publications

References 251 publications

Interaction of myelin basic protein with artificial membranes

Interaction of myelin basic protein with artificial membranes

Adsorption of Membrane-Associated Proteins to Lipid Bilayers Studied with an Atomic Force Microscope: Myelin Basic Protein and Cytochrome c

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