title: Interaction of myelin basic protein with cytoskeletal and signaling proteins in cultured primary oligodendrocytes and N19 oligodendroglial cells.
abstract: BACKGROUND
  The classic myelin basic protein (MBP) isoforms are intrinsically-disordered proteins of 14-21.5 kDa in size arising from the Golli (Gene in the Oligodendrocyte Lineage) gene complex, and are responsible for formation of the multilayered myelin sheath in the central nervous system. The predominant membrane-associated isoform of MBP is not simply a structural component of compact myelin but is highly post-translationally modified and multi-functional, having interactions with numerous proteins such as Ca2+-calmodulin, and with actin, tubulin, and proteins with SH3-domains, which it can tether to a lipid membrane in vitro. It co-localizes with such proteins in primary oligodendrocytes (OLGs) and in early developmental N19-OLGs transfected with fluorescently-tagged MBP.
  
  
  RESULTS
  To provide further evidence for MBP associations with these proteins in vivo, we show here that MBP isoforms are co-immunoprecipitated from detergent extracts of primary OLGs together with actin, tubulin, zonula occludens 1 (ZO-1), cortactin, and Fyn kinase. We also carry out live-cell imaging of N19-OLGs co-transfected with fluorescent MBP and actin, and show that when actin filaments re-assemble after recovery from cytochalasin D treatment, MBP and actin are rapidly enriched and co-localized at certain sites at the plasma membrane and in newly-formed membrane ruffles. The MBP and actin distributions change similarly with time, suggesting a specific and dynamic association.
  
  
  CONCLUSIONS
  These results provide more direct evidence for association of the predominant 18.5-kDa MBP isoform with these proteins in primary OLGs and in live cells than previously could be inferred from co-localization observations. This study supports further a role for classic MBP isoforms in protein-protein interactions during membrane and cytoskeletal extension and remodeling in OLGs.
authors: Molecular Structure and Function Program, Research Institute, Hospital for Sick Children, 686 Bay St, Toronto, ON M5G 0A4, Canada. jmboggs@sickkids.ca.
authors: Joan M
authors: JM
authors: Boggs
authors: Lopamudra
authors: L
authors: Homchaudhuri
authors: Godha
authors: G
authors: Ranagaraj
authors: Yuanfang
authors: Y
authors: Liu
authors: Graham S T
authors: GS
authors: Smith
authors: George
authors: G
authors: Harauz
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D051356:Cortactin / Q000235:genetics / Q000378:metabolism; D015638:Cytochalasin D / Q000494:pharmacology; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D004676:Myelin Basic Protein / Q000235:genetics / Q000378:metabolism*; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D009836:Oligodendroglia / Q000166:cytology / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D051076:Proto-Oncogene Proteins c-fyn / Q000235:genetics / Q000378:metabolism; D017208:Rats, Wistar; D014404:Tubulin / Q000235:genetics / Q000378:metabolism; D062826:Zonula Occludens-1 Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D051356:Cortactin; D003598:Cytoskeletal Proteins; D008164:Luminescent Proteins; D004676:Myelin Basic Protein; D019384:Nucleic Acid Synthesis Inhibitors; D020033:Protein Isoforms; D014404:Tubulin; D062826:Zonula Occludens-1 Protein; D015638:Cytochalasin D; C494960:Fyn protein, mouse; D051076:Proto-Oncogene Proteins c-fyn