Mapmodulin: a possible modulator of the interaction of microtubule-associated proteins with microtubules.
We have purified and characterized a 31-kDa protein named mapmodulin that binds to the microtubule-associated proteins (MAPs) MAP2, MAP4, and tau. Mapmodulin binds free MAPs in strong preference to microtubule-associated MAPs, and appears to do so via the MAP's tubulin-binding domain. Mapmodulin inhibits the initial rate of MAP2 binding to microtubules, a property that may allow mapmodulin to displace MAPs from the path of organelles translocating along microtubules. In support of this possibility, mapmodulin stimulates the microtubule- and dynein-dependent localization of Golgi complexes in semi-intact CHO cells. To our knowledge, mapmodulin represents the first example of a protein that can bind and potentially regulate multiple MAP proteins.
Ulitzur
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Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307, USA.
Humbert
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M
Pfeffer
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SR
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002850:Chromatography, Gel; D006224:Cricetinae; D003600:Cytosol; D004398:Dyneins / Q000737:chemistry / Q000502:physiology; D006056:Golgi Apparatus / Q000502:physiology; D007425:Intracellular Membranes / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology*; D008870:Microtubules / Q000502:physiology* / Q000648:ultrastructure; D008961:Models, Structural; D009687:Nuclear Proteins; D010446:Peptide Fragments / Q000737:chemistry; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology*; D016601:RNA-Binding Proteins
C087425:ANP32A protein, human; D047908:Intracellular Signaling Peptides and Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D010446:Peptide Fragments; D011506:Proteins; D016601:RNA-Binding Proteins; D004398:Dyneins