Solute carrier family 22 member 4 (SLC22A4 (OCTN1))

Solute carrier family 22 member 4 (SLC22A4), also known as organic cation transporter novel type 1 (OCTN1), encodes an integral membrane protein containing 12 transmembrane domains and functions as a Na⁺-dependent, high-affinity transporter for ergothioneine, an antioxidant amino acid. It also accepts a range of organic cations and zwitterions as substrates, showing low transport efficiency for carnitine and certain other molecules. OCTN1 is expressed in numerous tissues including liver, intestine, kidney, heart, brain, and placenta, implied to be important for antioxidant supply and cellular defense against oxidative stress. Genetic variants of SLC22A4 have been associated with susceptibility to inflammatory and autoimmune conditions. Correction Note: SLC22A4/OCTN1 is not a sodium/hydrogen exchanger. The sodium/hydrogen exchanger isoform 3 is encoded by a different gene, SLC9A3. Instead, SLC22A4 is primarily an ergothioneine and organic cation transporter.

Other names

Organic cation transporter 1 (OCTN1)Ergothioneine transporter (ETT)SLC22A4

Competitive inhibition (some drugs compete for transport) Substrate translocation across the plasma membrane