Recombinant Human OPN3 protein

Opsin 3 (OPN3), a member of the light-sensitive opsin family of G protein-coupled receptors (GPCRs), is implicated in non-visual phototransduction across various tissues. Unlike classical opsins like rhodopsin, OPN3 detects ultraviolet to blue light (∼380-500 nm) and is expressed in non-retinal tissues, including the brain, skin, adipose tissue, and immune cells. Its role extends beyond light sensing, potentially regulating circadian rhythms, thermogenesis, and cellular homeostasis. However, its precise signaling mechanisms and physiological functions remain partially characterized.

Recombinant OPN3 protein is engineered to study its structure, ligand interactions, and activation pathways. Produced via heterologous expression systems (e.g., HEK293. insect cells), it is purified using affinity tags (His-tag, FLAG) and chromatography. This recombinant form enables in vitro analysis of conformational changes upon light exposure, G protein coupling preferences, and downstream signaling cascades. Notably, OPN3 may activate Gi, Gq, or β-arrestin pathways, depending on cellular context, complicating functional studies.

Research highlights OPN3’s involvement in metabolic regulation, melanoma progression, and neuroprotection. For example, adipocyte OPN3 modulates lipid metabolism via light-dependent mechanisms, while neuronal OPN3 may influence mood disorders. Recombinant OPN3 also aids drug discovery, particularly for diseases linked to dysregulated phototransduction or GPCR signaling. Challenges include maintaining protein stability during purification and reconciling tissue-specific functional variations. Recent studies employ cryo-EM to resolve OPN3’s 3D structure, advancing mechanistic insights. Its dual roles in light-dependent and -independent processes make OPN3 a compelling therapeutic target, driving demand for high-purity recombinant variants to unravel its multifunctional biology.