title: Microtubule-associated protein 1B binds glyceraldehyde-3-phosphate dehydrogenase.
abstract: Microtubule-associated protein 1B, MAP1B, is a major cytoskeletal protein during brain development and one of the largest brain MAPs associated with microtubules and microfilaments. Here, we identified several proteins that bind to MAP1B via immunoprecipitation with a MAP1B-specific antibody, by one and two-dimensional gel electrophoresis and subsequent mass spectrometry identification of precipitated proteins. In addition to tubulin and actin, a variety of proteins were identified. Among these proteins were glyceraldehyde-3-phosphate dehydrogenase (GAPDH), heat shock protein 8, dihydropyrimidinase related proteins 2 and 3, protein-L-isoaspartate O-methyltransferase, beta-spectrin, and clathrin protein MKIAA0034, linking either directly or indirectly to MAP1B. In particular, GAPDH, a key glycolytic enzyme, was bound in large quantity to the heavy chain of MAP1B in adult brain tissue. In vitro binding studies confirmed a direct binding of GAPDH to MAP1B. In PC12 cells, GAPDH was found in cytoplasm and nuclei and partially co-localized with MAP1B. It disappeared from the cytoplasm under oxidative stress or after a disruption of cytoskeletal elements after colcemid or cytochalasin exposure. GAPDH may be essential in the local energy provision of cytoskeletal structures and MAP1B may help to keep this key enzyme close to the cytoskeleton.
authors.affiliation: Département de Biologie Cellulaire et de Morphologie (DBCM), Université de Lausanne, 9 Rue du Bugnon, 1005 Lausanne, Suisse.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Cueille
authors.forename: Corinne Tallichet
authors.initials: CT
authors.lastname: Blanc
authors.forename: Irène M
authors.initials: IM
authors.lastname: Riederer
authors.forename: Beat M
authors.initials: BM
authors.lastname: Riederer
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D001923:Brain Chemistry; D002467:Cell Nucleus / Q000737:chemistry; D003593:Cytoplasm / Q000737:chemistry; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000032:analysis / Q000378:metabolism*; D047468:Immunoprecipitation; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000032:analysis / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism
chemical_list: D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; C085284:microtubule-associated protein 1B; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases