Physiology and Function of the Tight Junction (original) (raw)

  1. James M. Anderson1 and
  2. Christina M. Van Itallie2
  3. 1Department of Cell and Molecular Physiology, University of North Carolina at Chapel Hill, 6312 MBRB, Chapel Hill, North Carolina 27599-7545
  4. 2Department of Medicine, Division of Gastroenterology and Hepatology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7545
  5. Correspondence: jandersn{at}med.unc.edu

Abstract

Understanding of tight junctions has evolved from their historical perception as inert solute barriers to recognition of their physiological and biochemical complexity. Many proteins are specifically localized to tight junctions, including cytoplasmic actin-binding proteins and adhesive transmembrane proteins. Among the latter are claudins, which are critical barrier proteins. Current information suggests that the paracellular barrier is most usefully modeled as having two physiologic components: a system of charge-selective small pores, 4 Å in radius, and a second pathway created by larger discontinuities in the barrier, lacking charge or size discrimination. The first pathway is influenced by claudin expression patterns and the second is likely controlled by different proteins and signals. Recent information on claudin function and disease-causing mutations have led to a more complete understanding of their role in barrier formation, but progress is impeded by lack of high resolution structural information.

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