A differentiation-dependent splice variant of myosin light chain kinase, MLCK1, regulates epithelial tight junction permeability

Daniel R. Clayburgh, Shari Rosen, Edwina D. Witkowski, Fengjun Wang, Stephanie Blair, Steven Dudek, Joe G.N. Garcia, John C. Alverdy, Jerrold R. Turner

Research output: Contribution to journalArticle

101 Scopus citations

Abstract

Activation of Na+-nutrient cotransport leads to increased tight junction permeability in intestinal absorptive (villus) enterocytes. This regulation requires myosin II regulatory light chain (MLC) phosphorylation mediated by MLC kinase (MLCK). We examined the spatio-temporal segregation of MLCK isoform function and expression along the crypt-villus axis and found that long MLCK, which is expressed as two alternatively spliced isoforms, accounts for 97 ± 4% of MLC kinase activity in interphase intestinal epithelial cells. Expression of the MLCK1 isoform is limited to well differentiated enterocytes, both in vitro and in vivo, and this expression correlates closely with development of Na+-nutrient cotransport-dependent tight junction regulation. Consistent with, this role, MLCK1 is localized to the perijunctional actomyosin ring. Furthermore, specific knockdown of MLCK1 using siRNA reduced tight junction permeability in monolayers with active Na +-glucose cotransport, confirming a functional role for MLCK1. These results demonstrate unique physiologically relevant patterns of expression and subcellular localization for long MLCK isoforms and show that MLCK1 is the isoform responsible for tight junction regulation in absorptive enterocytes.

Original languageEnglish (US)
Pages (from-to)55506-55513
Number of pages8
JournalJournal of Biological Chemistry
Volume279
Issue number53
DOIs
StatePublished - Dec 31 2004

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Clayburgh, D. R., Rosen, S., Witkowski, E. D., Wang, F., Blair, S., Dudek, S., Garcia, J. G. N., Alverdy, J. C., & Turner, J. R. (2004). A differentiation-dependent splice variant of myosin light chain kinase, MLCK1, regulates epithelial tight junction permeability. Journal of Biological Chemistry, 279(53), 55506-55513. https://doi.org/10.1074/jbc.M408822200