Calcium-dependent lectin that acts as a pattern recognition receptor (PRR) of the innate immune system: recognizes damage- associated molecular patterns (DAMPs) of pathogen-associated molecular patterns (PAMPs) of bacteria and fungi (PubMed:23602766, PubMed:23911656). The PAMPs include alpha-mannans on C.albicans hypheas and mycobacterial trehalose 6,6'-dimycolate (TDM) (PubMed:23602766, PubMed:23911656). Interacts with signaling adapter Fc receptor gamma chain/FCER1G, likely via CLEC4E, to form a functional complex in myeloid cells (By similarity). Binding of mycobacterial TDM or C.albicans alpha-mannans to this receptor complex leads to phosphorylation of the immunoreceptor tyrosine-based activation motif (ITAM) of FCER1G, triggering activation of SYK, CARD9 and NF-kappa-B, consequently driving maturation of antigen-presenting cells and shaping antigen-specific priming of T-cells toward effector T-helper 1 and T- helper 17 cell subtypes (PubMed:23602766, PubMed:23911656). The heterodimer formed with CLEC6A is active against fungal infection (PubMed:23911656). Functions as an endocytic receptor (PubMed:14971047). May be involved in antigen uptake at the site of infection, either for clearance of the antigen, or for processing and further presentation to T-cells (PubMed:14971047). {ECO:0000250|UniProtKB:Q69FH1, ECO:0000269|PubMed:14971047, ECO:0000269|PubMed:23602766, ECO:0000269|PubMed:23911656}. This is the function of ENSG00000166527 (CLEC4D, C-type lectin domain family 4 member D).