Human macrophage C-type lectin forms a heteromeric receptor complex with Mincle but not Dectin-2

Area of Science:

• Immunology
• Cell Biology
• Molecular Biology

Background:

• C-type lectin receptors (CLRs) like MCL, Mincle, and Dectin-2 are expressed on myeloid cells.
• These CLRs are involved in immune responses and their genes are located in the APLEC/Dectin-2 gene complex.
• Previous studies indicated heterodimer formation between MCL and Mincle in rats, and MCL and Dectin-2 in mice.

Purpose of the Study:

• To investigate the association of human MCL, Mincle, and Dectin-2 receptors.
• To determine the heterodimerization patterns and interactions with the FcεRIγ signaling adaptor in human myeloid cells.

Main Methods:

• Co-transfection experiments were performed to express the human receptors.
• Flow cytometry and immunoprecipitation assays were utilized to analyze receptor associations.
• Disulfide linkage and heterodimer formation were assessed.

Main Results:

• Human MCL and Mincle form a disulfide-linked heterodimer that associates with FcεRIγ.
• Direct association between human MCL and FcεRIγ was observed.
• No heterodimer formation was detected between human MCL and Dectin-2.

Conclusions:

• Human MCL and Mincle heterodimerization with FcεRIγ is conserved from rat studies.
• Unlike mouse and rat findings, human MCL does not appear to heterodimerize with Dectin-2.
• Species-specific differences in CLR conformation may exist, potentially impacting immune signaling functions.