How C-type lectins detect pathogens

Abstract

Glycosylation of proteins has proven extremely important in a variety of cellular processes, including enzyme trafficking, tissue homing and immune functions. In the past decade, increasing interest in carbohydrate‐mediated mechanisms has led to the identification of novel carbohydrate‐recognizing receptors expressed on cells of the immune system. These non‐enzymatic lectins contain one or more carbohydrate recognition domains (CRDs) that determine their specificity. In addition to their cell adhesion functions, lectins now also appear to play a major role in pathogen recognition. Depending on their structure and mode of action, lectins are subdivided in several groups. In this review, we focus on the calcium (Ca²⁺)‐dependent lectin group, known as C‐type lectins, with the dendritic cell‐specific ICAM‐3 grabbing non‐integrin (DC‐SIGN) as a prototype type II C‐type lectin organized in microdomains, and their role as pathogen recognition receptors in sensing microbes. Moreover, the cross‐talk of C‐type lectins with other receptors, such as Toll‐like receptors, will be discussed, highlighting the emerging model that microbial recognition is based on a complex network of interacting receptors.