CLIPR-59, a new trans-Golgi/TGN cytoplasmic linker protein belonging to the CLIP-170 family.
The microtubule cytoskeleton plays a fundamental role in cell organization and membrane traffic in higher eukaryotes. It is well established that molecular motors are involved in membrane-microtubule interactions, but it has also been proposed that nonmotor microtubule-binding (MTB) proteins known as CLIPs (cytoplasmic linker proteins) have basic roles in these processes. We report here the characterization of CLIPR-59, a CLIP-170-related protein localized to the trans-most part of the Golgi apparatus. CLIPR-59 contains an acidic region followed by three ankyrin-like repeats and two CLIP-170-related MTB motifs. We show that the 60-amino acid-long carboxy-terminal domain of CLIPR-59 is necessary and sufficient to achieve Golgi targeting, which represents the first identification of a membrane targeting domain in a CLIP-170-related protein. The MTB domain of CLIPR-59 is functional because it localizes to microtubules when expressed as a fragment in HeLa cells. However, our results suggest that this domain is normally inhibited by the presence of adjacent domains, because neither full-length CLIPR-59 nor a CLIPR-59 mutant missing its membrane-targeting region localize to microtubules. Consistent with this observation, overexpression of CLIPR-59 does not affect the microtubule network. However, CLIPR-59 overexpression strongly perturbs early/recycling endosome-TGN dynamics, implicating CLIPR-59 in the regulation of this pathway.
Perez
Franck
F
Institut Curie, CNRS UMR144, 75248 Paris, France. franck.perez@curie.fr
Pernet-Gallay
Karin
K
Nizak
Clément
C
Goodson
Holly V
HV
Kreis
Thomas E
TE
Goud
Bruno
B
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary; D011992:Endosomes / Q000378:metabolism / Q000502:physiology; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism / Q000502:physiology; D008869:Microtubule-Associated Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D011817:Rabbits; D021601:trans-Golgi Network / Q000378:metabolism*
C449670:CLIP3 protein, human; D018076:DNA, Complementary; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; C076744:cytoplasmic linker protein 170