Cellular and Molecular Life Sciences CMLS

, Volume 59, Issue 4, pp 648–664 | Cite as

CD23 (the low-affinity IgE receptor) as a C-type lectin: a multidomain and multifunctional molecule

  • S. Kijimoto-Ochiai


This review, regards the low-affinity receptor CD23 as a C-type lectin and compares it with other C-type lectins and C-type lectin-like receptors. C-type lectins such as the asialoglycoprotein receptor, as well as the dendritic cell immunoreceptor and the dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin on dendritic cell lectin, possess amino acid sequences which interact with Ca++ and sugar, and many of them possess an endocytosis signal sequence that includes tyrosine or serine in the cytoplasmic region. In contrast, natural killer receptors lack the Ca++ and sugar-binding amino acids but conserve homologous cysteines in the form of C-type lectin, and possess an immunoreceptor tyrosine-based inhibitory motif in the cytoplasmic region which inhibits killer activity when they recognize the self major histocompatibility (MHC) class I molecule. Since human CD23a form has a similar amino acid sequence, the possibility that this sequence is an endocytosis signal or an ITIM is discussed. The function of the reverse RGD and RGD-binding inhibitory peptide in human CD23 from the point of view of the relation between a C-type lectin and MHC class II molecules is also considered.

Key words. Low-affinity receptor for IgE; CD23; NK receptor; C-type lectin(-like) domain; inverse RGD sequence; RGD-binding inhibitory peptide; ITIM, endocytosis signal. 


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Copyright information

© Birkhäuser Verlag, 2002

Authors and Affiliations

  • S. Kijimoto-Ochiai
    • 1
  1. 1.Institute of Immunology and Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815 (Japan)JP

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