CD300A Human

CD300A is a type I transmembrane receptor characterized by an extracellular IgV-like domain and a cytoplasmic tail containing three classic immunoreceptor tyrosine-based inhibitory motifs (ITIMs) . These ITIMs are essential for the inhibitory signaling functions of CD300A. The receptor is broadly expressed on various immune cells, including myeloid and lymphoid cells .

CD300A recognizes and binds to specific lipids, such as phosphatidylserine and phosphatidylethanolamine, which are exposed on the outer leaflet of the plasma membrane of dead and activated cells . Upon ligand binding, the ITIMs in the cytoplasmic tail of CD300A become phosphorylated, initiating a cascade of inhibitory signals that modulate immune cell functions .

The primary function of CD300A is to inhibit immune cell activation and maintain immune homeostasis. It achieves this by dampening the activation signals from other receptors. For instance, CD300A can inhibit natural killer (NK) cell-mediated cytotoxicity, FcγRIIa-mediated reactive oxygen species production in neutrophils, and FcϵRI-mediated activation of mast cells . This inhibitory function is crucial in preventing excessive immune responses and maintaining tolerance to self-antigens .

CD300A has significant clinical relevance due to its role in various pathological conditions. It has been implicated in the pathogenesis of infectious diseases, cancer, allergies, and chronic inflammatory diseases . For example, in a murine model of asthma, targeting CD300A with a bispecific antibody linking it to CCR3 reversed airway inflammation and remodeling . Additionally, CD300A has been studied as a potential therapeutic target for modulating immune responses in various disease states .

Recombinant CD300A is a laboratory-produced version of the natural protein, designed to mimic its structure and function. It is used in research to study the receptor’s role in immune regulation and to develop potential therapeutic interventions. Recombinant proteins are typically produced using expression systems such as bacteria, yeast, or mammalian cells, and are purified to ensure their functionality and stability.