About this Research Topic
C-type lectin receptors (CLRs) constitute a large and diverse family of proteins containing at least one C-type lectin-like domain (CTLD). These proteins were originally named for their ability to bind carbohydrates in a Ca2+-dependent manner but since many CTLD-containing proteins have been identified that interact with ligands independently of the presence of Ca2+ and able to recognize non-carbohydrate ligands. In mammals, subsets of CLRs are expressed by immune cells, with expression patterns dependent on cell type as well as cellular differentiation and activation state.
The domain composition of CLRs as well as the ability to influence cellular activity varies greatly. While some CLRs hold an intracellular immunoreceptor tyrosine-based activating motif (ITAM), others bear an inhibiting motif or lack canonical signaling motifs. Similarly, some CLRs are largely involved in cellular adhesion events and while others play an important role in ligand internalization, indicating high functional diversity within this family of receptors. This would agree with the breadth of endogenous and microbial CLRs ligands and the lack of hard-wired cellular responses after CLRs engagement. In addition, changes in the repertoire of CLRs expression alongside the presence of other pattern recognition receptors with robust signaling ability expands the range of potential responses. Accordingly, the consequences of ligand binding to CTL receptors may differ extensively, e.g. give rise to highly diverse intracellular signaling followed by e.g. cell activation and production of specific cytokine patterns. One example is the diverging effects of activating CLRs may have if they are present simultaneously with Gram-positive or Gram-negative bacteria. Another newly reported activity is the putative effect of CLRs on the differentiation of myeloid cells. Although we today have much insight into the diverse roles of CLRs in immunity, there is still much to discover and understand.
Therefore, in this Research Topic we welcome the submission of Original Research, Review, Mini Review articles, which cover, but are not limited to, the following subtopics :
1. The effect of CLRs ligation by soluble as opposed to particulate ligands
2. How signaling outcome is affected by co-engagement of CLRs and other pattern recognition receptors such as Toll-Like Receptors
3. The effect of CLRs ligation during immune cell differentiation
Keywords: C-type Lectin Receptors, CLRs
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