Centrosomal CAP350 protein stabilises microtubules associated with the Golgi complex.
A comprehensive model of how the centrosome organises the microtubule network in animal cells has not yet been elucidated. Here we show that the centrosomal large CAP-Gly protein CAP350 is not only present at the centrosome, but is also present as numerous dots in the pericentrosomal area. Using in vitro and in vivo expression of partial constructs, we demonstrated that CAP350 binds microtubules through an N-terminal basic region rather than through its CAP-Gly domain. CAP-Gly-containing domains of CAP350 are targeted not only to the centrosome but also to a Golgi-like network. Interestingly, full-length GFP-tagged CAP350 bound preferentially to microtubules in the pericentrosomal area. These results indicate that the large CAP350 protein has a dual binding ability. Overexpression of CAP350 promoted an increase in the stability of the whole microtubule network, as judged by a significant decrease in the number of EB1 comets and by an enhanced microtubule resistance to Nocodazole treatment. In support of this, CAP350 depletion decreased microtubule stability. Moreover, both depletion and overexpression of CAP350 induced specific fragmentation of the Golgi complex while maintaining a juxtanuclear localisation. We propose that CAP350 specifically stabilises Golgi-associated microtubules and in this way participates in the maintenance of a continuous pericentrosomal Golgi ribbon.
Hoppeler-Lebel
Aurélie
A
Institut Curie, Section Recherche, UMR144-CNRS, 75248 Paris CEDEX, France.
Celati
Claude
C
Bellett
Gemma
G
Mogensen
Mette M
MM
Klein-Hitpass
Ludger
L
Bornens
Michel
M
Tassin
Anne-Marie
AM
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D018385:Centrosome / Q000378:metabolism*; D004285:Dogs; D004351:Drug Resistance / Q000235:genetics; D015870:Gene Expression / Q000235:genetics; D006056:Golgi Apparatus / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008868:Microtubule Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000235:genetics / Q000378:metabolism*; D015739:Nocodazole / Q000494:pharmacology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics
D000970:Antineoplastic Agents; C509238:CEP350 protein, human; D008868:Microtubule Proteins; D009687:Nuclear Proteins; D015739:Nocodazole