Phosphorylation of Rab11-FIP2 regulates polarity in MDCK cells.

Lapierre LA, Avant KM, Caldwell CM, Oztan A, Apodaca G, Knowles BC, Roland JT, Ducharme NA, Goldenring JR
Mol Biol Cell. 2012 23 (12): 2302-18

PMID: 22553350 · PMCID: PMC3374749 · DOI:10.1091/mbc.E11-08-0681

The Rab11 effector Rab11-family interacting protein 2 (Rab11-FIP2) regulates transcytosis through its interactions with Rab11a and myosin Vb. Previous studies implicated Rab11-FIP2 in the establishment of polarity in Madin-Darby canine kidney (MDCK) cells through phosphorylation of Ser-227 by MARK2. Here we examine the dynamic role of Rab11-FIP2 phosphorylation on MDCK cell polarity. Endogenous Rab11-FIP2 phosphorylated on Ser-227 coalesces on vesicular plaques during the reestablishment of polarity after either monolayer wounding or calcium switch. Whereas expression of the nonphosphorylatable Rab11-FIP2(S227A) elicits a loss in lumen formation in MDCK cell cysts grown in Matrigel, the putative pseudophosphorylated Rab11-FIP2(S227E) mutant induces the formation of cysts with multiple lumens. On permeable filters, Rab11-FIP2(S227E)-expressing cells exhibit alterations in the composition of both the adherens and tight junctions. At the adherens junction, p120 catenin and K-cadherin are retained, whereas the majority of the E-cadherin is lost. Although ZO-1 is retained at the tight junction, occludin is lost and the claudin composition is altered. Of interest, the effects of Rab11-FIP2 on cellular polarity did not involve myosin Vb or Rab11a. These results indicate that Ser-227 phosphorylation of Rab11-FIP2 regulates the composition of both adherens and tight junctions and is intimately involved in the regulation of polarity in epithelial cells.

MeSH Terms (23)

Adherens Junctions Animals Blotting, Western Cadherins Catenins Cell Line Cell Polarity Claudins Dogs Epithelial Cells Green Fluorescent Proteins HEK293 Cells Humans Kidney Membrane Proteins Microscopy, Confocal Mutation Occludin Phosphorylation Reverse Transcriptase Polymerase Chain Reaction Serine Tight Junctions Vesicular Transport Proteins

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