GMAP-210, A cis-Golgi network-associated protein, is a minus end microtubule-binding protein.
We report that a peripheral Golgi protein with a molecular mass of 210 kD localized at the cis-Golgi network (Rios, R.M., A.M. Tassin, C. Celati, C. Antony, M.C. Boissier, J.C. Homberg, and M. Bornens. 1994. J. Cell Biol. 125:997-1013) is a microtubule-binding protein that associates in situ with a subpopulation of stable microtubules. Interaction of this protein, now called GMAP-210, for Golgi microtubule-associated protein 210, with microtubules in vitro is direct, tight and nucleotide-independent. Biochemical analysis further suggests that GMAP-210 specifically binds to microtubule ends. The full-length cDNA encoding GMAP-210 predicts a protein of 1, 979 amino acids with a very long central coiled-coil domain. Deletion analyses in vitro show that the COOH terminus of GMAP-210 binds to microtubules whereas the NH2 terminus binds to Golgi membranes. Overexpression of GMAP-210-encoding cDNA induced a dramatic enlargement of the Golgi apparatus and perturbations in the microtubule network. These effects did not occur when a mutant lacking the COOH-terminal domain was expressed. When transfected in fusion with the green fluorescent protein, the NH2-terminal domain associated with the cis-Golgi network whereas the COOH-terminal microtubule-binding domain localized at the centrosome. Altogether these data support the view that GMAP-210 serves to link the cis-Golgi network to the minus ends of centrosome-nucleated microtubules. In addition, this interaction appears essential for ensuring the proper morphology and size of the Golgi apparatus.
Infante
C
C
Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla Apdo. 1095, 41080-Sevilla, Spain.
Ramos-Morales
F
F
Fedriani
C
C
Bornens
M
M
Rios
R M
RM
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D018385:Centrosome / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary / Q000235:genetics; D017930:Genes, Reporter; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D007399:Interphase; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D008870:Microtubules / Q000378:metabolism*; D020409:Molecular Motor Proteins; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009687:Nuclear Proteins; D017239:Paclitaxel / Q000378:metabolism / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017384:Sequence Deletion; D014162:Transfection; D014404:Tubulin / Q000378:metabolism
D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins; D020409:Molecular Motor Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; C109331:TRIP11 protein, human; D014404:Tubulin; D049452:Green Fluorescent Proteins; D017239:Paclitaxel