Cell surface receptors are responsible for regulating cellular function on the front line, the cell membrane. Interestingly, accumulating evidence clearly reveals that the members of cell surface receptor families have very similar extracellular ligand-binding regions but opposite signaling systems, either inhibitory or stimulatory. These receptors are designated as paired receptors. Paired receptors often recognize not only physiological ligands but also non-self ligands, such as viral and bacterial products, to fight infections. In this review, we introduce several representative examples of paired receptors, focusing on two major structural superfamilies, the immunoglobulin-like and the C-type lectin-like receptors, and explain how these receptors distinguish self and non-self ligands to maintain homeostasis in the immune system. We further discuss the evolutionary aspects of these receptors as well as the potential drug targets for regulating diseases.
Keywords: paired receptor, immunoglobulin-like receptor, c-type lectin-like receptor, infectious diseases, tumorigenesis, ITIM, ITAM, structural biology
Citation: Kuroki K, Furukawa A and Maenaka K (2012) Molecular recognition of paired receptors in the immune system. Front. Microbio. 3:429. doi: 10.3389/fmicb.2012.00429
Received: 15 August 2012; Paper pending published: 04 September 2012;
Accepted: 06 December 2012; Published online: 31 December 2012.
Edited by:Hironori Sato, National Institute of Infectious Diseases, Japan
Reviewed by:Hidekatsu Iha, Oita University, Japan
Copyright: © 2012 Kuroki, Furukawa and Maenaka. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
*Correspondence: Katsumi Maenaka, Laboratory of Biomolecular Science, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan. e-mail: firstname.lastname@example.org