Medical Electron Microscopy

, Volume 36, Issue 3, pp 147–156

Tight junctions and human diseases

  • Norimasa Sawada
  • Masaki Murata
  • Keisuke Kikuchi
  • Makoto Osanai
  • Hirotoshi Tobioka
  • Takashi Kojima
  • Hideki Chiba
REVIEW

DOI: 10.1007/s00795-003-0219-y

Cite this article as:
Sawada, N., Murata, M., Kikuchi, K. et al. Med Electron Microsc (2003) 36: 147. doi:10.1007/s00795-003-0219-y

Abstract

Tight junctions are intercellular junctions adjacent to the apical end of the lateral membrane surface. They have two functions, the barrier (or gate) function and the fence function. The barrier function of tight junctions regulates the passage of ions, water, and various macromolecules, even of cancer cells, through paracellular spaces. The barrier function is thus relevant to edema, jaundice, diarrhea, and blood-borne metastasis. On the other hand, the fence function maintains cell polarity. In other words, tight junctions work as a fence to prevent intermixing of molecules in the apical membrane with those in the lateral membrane. This function is deeply involved in cancer cell biology, in terms of loss of cell polarity. Of the proteins comprising tight junctions, integral membrane proteins occludin, claudins, and JAMs have been recently discovered. Of these molecules, claudins are exclusively responsible for the formation of tight-junction strands and are connected with the actin cytoskeleton mediated by ZO-1. Thus, both functions of tight junctions are dependent on the integrity of the actin cytoskeleton as well as ATP. Mutations in the claudin14 and the claudin16 genes result in hereditary deafness and hereditary hypomagnesemia, respectively. Some pathogenic bacteria and viruses target and affect the tight-junction function, leading to diseases. In this review, the relationship between tight junctions and human diseases is summarized.

Key words

Tight junctionsBarrier functionFence functionClaudinOccludinZO-1Human diseasesDrug delivery

Copyright information

© Springer-Verlag Tokyo 2003

Authors and Affiliations

  • Norimasa Sawada
    • 1
  • Masaki Murata
    • 1
  • Keisuke Kikuchi
    • 1
  • Makoto Osanai
    • 1
  • Hirotoshi Tobioka
    • 1
  • Takashi Kojima
    • 1
  • Hideki Chiba
    • 1
  1. 1.Department of PathologySapporo Medical University School of MedicineSapporoJapan