EWI-2 is a new component of the tetraspanin web in hepatocytes and lymphoid cells

Biochem J. 2003 Jul 15;373(Pt 2):409-21. doi: 10.1042/BJ20030343.


Several tetraspanins bind directly to a few molecular partners to form primary complexes, which might assemble through tetraspanin-tetraspanin interactions to form a network of molecular interactions, the tetraspanin web. We have produced a monoclonal antibody directed to a 63 kDa molecule (determined under non-reducing conditions) associated with CD9. This molecule was first identified by MS as a molecule with four Ig domains, EWI-2. Like the related molecule CD9P-1, EWI-2 was found to be a partner not only for CD9, but also for CD81, a tetraspanin required for hepatic infection by the parasite responsible for malaria, and also a putative hepatitis C virus receptor. Using chimaeric CD9/CD82 molecules, two separate regions of CD9 of 40 and 47 amino acids were demonstrated to confer the ability to interact with EWI-2. Both EWI-2 and CD9P-1 were detected in the human liver at the surface of hepatocytes and were found to associate with CD81 on freshly isolated hepatocytes. EWI-2 also co-localized with CD81 in the liver. CD9P-1 was not detected on most peripheral blood cells, whereas EWI-2 was expressed on the majority of B-, T- and natural killer cells and was not detected on monocytes, polynuclear cells or platelets. This distribution is identical to that of CD81. Finally, EWI-2 associated with all tetraspanins studied after lysis under conditions preserving tetraspanin-tetraspanin interactions, showing that EWI-2 is a new component of the tetraspanin web.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal
  • Antigens, CD / metabolism*
  • CHO Cells
  • Cricetinae
  • DNA Primers
  • Fluorescent Antibody Technique
  • Hepatocytes / metabolism*
  • Hepatocytes / pathology
  • Humans
  • Immunoglobulins / immunology
  • Immunoglobulins / metabolism*
  • Lymphocytes / metabolism*
  • Lymphocytes / pathology
  • Membrane Glycoproteins / metabolism*
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Microscopy, Confocal
  • Molecular Sequence Data
  • Plasmids
  • Polymerase Chain Reaction
  • Precipitin Tests
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Tetraspanin 28
  • Tetraspanin 29
  • Tumor Cells, Cultured


  • Antibodies, Monoclonal
  • Antigens, CD
  • CD81 protein, human
  • CD9 protein, human
  • Cd81 protein, mouse
  • Cd9 protein, mouse
  • DNA Primers
  • IGSF8 protein, human
  • Immunoglobulins
  • Membrane Glycoproteins
  • Membrane Proteins
  • Tetraspanin 28
  • Tetraspanin 29

Associated data

  • GENBANK/AY044845