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Mol. Biol. Cell 24 (6): 818-831

Copyright © 2013 by The American Society for Cell Biology.


Membrane Trafficking

Rab25 regulates integrin expression in polarized colonic epithelial cells

Moorthy Krishnana, Lynne A. Lapierrea,b, Byron C. Knowlesa,c, and James R. Goldenringa,b,c,d,1

aSection of Surgical Sciences and the Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232 cDepartment of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232 dVanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37232 bNashville Veterans Affairs Medical Center, Nashville, TN 37212

Received for publication October 16, 2012. Revision received December 20, 2012. Accepted for publication January 16, 2013.

Monitoring Editor: Benjamin Margolis

Abstract: Rab25 is a tumor suppressor for colon cancer in humans and mice. To identify elements of intestinal polarity regulated by Rab25, we developed Caco2-BBE cell lines stably expressing short hairpin RNA for Rab25 and lines rescuing Rab25 knockdown with reexpression of rabbit Rab25. Rab25 knockdown decreased α2-, α5-, and β1-integrin expression. We observed colocalization and direct association of Rab25 with α5β1-integrins. Rab25 knockdown also up-regulated claudin-1 expression, increased transepithelial resistance, and increased invasive behavior. Rab25-knockdown cells showed disorganized brush border microvilli with decreases in villin expression. All of these changes were reversed by reintroduction of rabbit Rab25. Rab25 knockdown altered the expression of 29 gene transcripts, including the loss of α5-integrin transcripts. Rab25 loss decreased expression of one transcription factor, ETV4, and overexpression of ETV4 in Rab25-knockdown cells reversed losses of α5β1-integrin. The results suggest that Rab25 controls intestinal cell polarity through the regulation of gene expression.


This article was published online ahead of print in MBoC in Press (http://www.molbiolcell.org/cgi/doi/10.1091/mbc.E12-10-0745) on January 23, 2013.

M.K. performed experiments, prepared figures, and cowrote the manuscript; L.A.L. performed experiments and reviewed the manuscript; B.C.K. performed experiments and cowrote the manuscript; J.R.G. designed experiments, prepared figures, and cowrote the manuscript.

None of the authors has any conflict of interest.

1Address correspondence to: James R. Goldenring (jim.goldenring{at}vanderbilt.edu).

Abbreviations: EGF, epidermal growth factor • ETV4, translocation variant 4 • KD, knockdown • RT-PCR, reverse transcription-PCR • shRNA, short hairpin RNA • SI, sucrase Isomaltase • TER, transepithelial resistance


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