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Characterization of Novel Rab6‐Interacting Proteins Involved in Endosome‐to‐TGN Transport
Author(s) -
Monier Solange,
Jollivet Florence,
JanoueixLerosey Isabelle,
Johannes Ludger,
Goud Bruno
Publication year - 2002
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1034/j.1600-0854.2002.030406.x
Subject(s) - rab , biology , endosome , microbiology and biotechnology , golgi apparatus , cytosol , protein subunit , transport protein , gtpase , intracellular , biochemistry , gene , enzyme , endoplasmic reticulum
Rab6 GTPase regulates intracellular transport at the level of the Golgi complex. Using the yeast two‐hybrid screen, we have isolated two clones that specifically interact with the three isoforms of Rab6 present in mammalian cells (Rab6A, A′ and B). The cDNAs encode two proteins of 976 and 1120 amino acids (calculated molecular mass of 112 and 128 kDa, respectively) that we named Rab6IP2A and Rab6IP2B (for Rab6 Interacting Protein 2). The two proteins likely correspond to spliced variants of the same gene. Rab6IP2s have no significant homology with other known proteins, including Rab effectors or partners. They are ubiquitously expressed, mostly cytosolic and found in high molecular mass complexes in brain cytosol. We show that Rab6IP2s can be recruited on Golgi membranes in a Rab6:GTP‐dependent manner. The overexpression of any form of Rab6IP2 has no detectable effect on the secretory pathway. In contrast, the retrograde transport of the Shiga toxin B subunit between the plasma membrane and the Golgi complex is partly inhibited in cells overexpressing the Rab6‐binding domain of Rab6IP2. Our data suggest that Rab6IP2s is involved in the pathway regulated by Rab6A′.