title: C11ORF24 is a novel type I membrane protein that cycles between the Golgi apparatus and the plasma membrane in Rab6-positive vesicles.
abstract: The Golgi apparatus is an intracellular compartment necessary for post-translational modification, sorting and transport of proteins. It plays a key role in mitotic entry through the Golgi mitotic checkpoint. In order to identify new proteins involved in the Golgi mitotic checkpoint, we combine the results of a knockdown screen for mitotic phenotypes and a localization screen. Using this approach, we identify a new Golgi protein C11ORF24 (NP_071733.1). We show that C11ORF24 has a signal peptide at the N-terminus and a transmembrane domain in the C-terminal region. C11ORF24 is localized on the Golgi apparatus and on the trans-Golgi network. A large part of the protein is present in the lumen of the Golgi apparatus whereas only a short tail extends into the cytosol. This cytosolic tail is well conserved in evolution. By FRAP experiments we show that the dynamics of C11ORF24 in the Golgi membrane are coherent with the presence of a transmembrane domain in the protein. C11ORF24 is not only present on the Golgi apparatus but also cycles to the plasma membrane via endosomes in a pH sensitive manner. Moreover, via video-microscopy studies we show that C11ORF24 is found on transport intermediates and is colocalized with the small GTPase RAB6, a GTPase involved in anterograde transport from the Golgi to the plasma membrane. Knocking down C11ORF24 does not lead to a mitotic phenotype or an intracellular transport defect in our hands. All together, these data suggest that C11ORF24 is present on the Golgi apparatus, transported to the plasma membrane and cycles back through the endosomes by way of RAB6 positive carriers.
authors: UMR144, Institut Curie/ CNRS, Cell and Tissue Imaging Platform, Paris, France.
authors: Vincent
authors: V
authors: Fraisier
authors: Amal
authors: A
authors: Kasri
authors: Stéphanie
authors: S
authors: Miserey-Lenkei
authors: Jean-Baptiste
authors: JB
authors: Sibarita
authors: Deepak
authors: D
authors: Nair
authors: Adeline
authors: A
authors: Mayeux
authors: Sabine
authors: S
authors: Bardin
authors: Yusuke
authors: Y
authors: Toyoda
authors: Ina
authors: I
authors: Poser
authors: Andrei
authors: A
authors: Poznyakovskiy
authors: Bruno
authors: B
authors: Goud
authors: Anthony A
authors: AA
authors: Hyman
authors: Ariane
authors: A
authors: Dimitrov
mesh_terms: D002453:Cell Cycle / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000502:physiology; D020691:rab GTP-Binding Proteins / Q000378:metabolism*
chemical_list: C433887:C11orf24 protein, human; D008565:Membrane Proteins; C094135:Rab6 protein; D020691:rab GTP-Binding Proteins