Solute carrier family 22 member 5 (SLC22A5) (OCTN2)

Solute carrier family 22 member 5 (SLC22A5), commonly known as OCTN2, is a multi-pass membrane protein that functions as a sodium-dependent high-affinity carnitine transporter and a sodium-independent organic cation transporter (UniProt: O76082). It is predominantly expressed in the kidney, heart, skeletal muscle, and placenta, playing a pivotal role in carnitine homeostasis by facilitating renal reabsorption and cellular uptake (NCBI Gene: 6584). Carnitine is an essential cofactor for the transport of long-chain fatty acids into the mitochondrial matrix for beta-oxidation, making OCTN2 critical for cellular energy metabolism (PubMed: 10438500). Mutations in the SLC22A5 gene are the underlying cause of systemic primary carnitine deficiency, a condition that can manifest as progressive cardiomyopathy, skeletal muscle weakness, and episodes of hypoketotic hypoglycemia (StatPearls: NBK557415). Furthermore, OCTN2 interacts with a variety of pharmacological agents, including levocarnitine, which is used as a replacement therapy, and various drugs like valproic acid and certain antibiotics that can inhibit its activity (DrugBank: DB00625). This interaction makes OCTN2 a key determinant in drug disposition and a potential site for clinically significant drug-drug interactions.

Other names

Organic cation transporter 2Carnitine transporterCDSPSCDSLC22A5

OCTN2 facilitates the sodium-dependent transport of L-carnitine across the plasma membrane, which is essential for fatty acid metabolism, and also mediates the sodium-independent transport of various organic cations and drugs (PubMed: 10438500). Therapeutic interventions involve using the transporter for drug delivery or managing its inhibition by xenobiotics to prevent carnitine depletion (DrugBank: DB00625).