TBC1D9B functions as a GTPase-activating protein for Rab11a in polarized MDCK cells

Luciana I. Gallo, Yong Liao, Wily G. Ruiz, Dennis R. Clayton, Min Li, Yong Jian Liu, Yu Jiange, Mitsunori Fukuda, Gerard Apodaca, Xiao Ming Yin

Research output: Contribution to journalArticle

21 Scopus citations


Rab11a is a key modulator of vesicular trafficking processes, but there is limited information about the guanine nucleotide-exchange factors and GTPase-activating proteins (GAPs) that regulate its GTP-GDP cycle. We observed that in the presence of Mg2+ (2.5 mM), TBC1D9B interacted via its Tre2-Bub2-Cdc16 (TBC) domain with Rab11a, Rab11b, and Rab4a in a nucleotide-dependent manner. However, only Rab11a was a substrate for TBC1D9B-stimulated GTP hydrolysis. At limiting Mg2+ concentrations (<0.5 mM), Rab8a was an additional substrate for this GAP. In polarized Madin-Darby canine kidney cells, endogenous TBC1D9B colocalized with Rab11a-positive recycling endosomes but less so with EEA1-positive early endosomes, transferrin-positive recycling endosomes, or late endosomes. Overexpression of TBC1D9B, but not an inactive mutant, decreased the rate of basolateral-to-apical IgA transcytosis-a Rab11a-dependent pathway-and shRNA-mediated depletion of TBC1D9B increased the rate of this process. In contrast, TBC1D9B had no effect on two Rab11a-independent pathways-basolateral recycling of the transferrin receptor or degradation of the epidermal growth factor receptor. Finally, expression of TBC1D9B decreased the amount of active Rab11a in the cell and concomitantly disrupted the interaction between Rab11a and its effector, Sec15A. We conclude that TBC1D9B is a Rab11a GAP that regulates basolateral-to-apical transcytosis in polarized MDCK cells.

Original languageEnglish (US)
Pages (from-to)3779-3797
Number of pages19
JournalMolecular Biology of the Cell
Issue number23
StatePublished - Nov 15 2014

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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    Gallo, L. I., Liao, Y., Ruiz, W. G., Clayton, D. R., Li, M., Liu, Y. J., Jiange, Y., Fukuda, M., Apodaca, G., & Yin, X. M. (2014). TBC1D9B functions as a GTPase-activating protein for Rab11a in polarized MDCK cells. Molecular Biology of the Cell, 25(23), 3779-3797. https://doi.org/10.1091/mbc.E13-10-0604