Related Experiment Video
Updated: Aug 21, 2026

Selection of Transporter-Targeted Inhibitory Nanobodies by Solid-Supported-Membrane (SSM)-Based Electrophysiology
Published on: May 3, 2021
Functional regions of organic cation/carnitine transporter OCTN2 (SLC22A5): roles in carnitine recognition
Akihiro Inano1, Yoshimichi Sai, Yukio Kato
1Faculty of Pharmaceutical Sciences, Kanazawa University, Japan.
Abstract:
The organic cation/carnitine transporter OCTN2 transports carnitine in a sodium-dependent manner, whereas it transports organic cations sodium-independently. To elucidate the functional domain in OCTN2, we constructed chimeric proteins of human OCTN2 (hOCTN2) and mouse OCTN3 (mOCTN3) and introduced mutations at several amino acids conserved among human, rat and mouse OCTN2. We found that transmembrane domains (TMD) 1-7 are responsible for organic cation transport and for sodium dependence in carnitine transport. Within TMD1-7, Q180 and Q207 of hOCTN2 are the critical amino acids for the sodium dependence, and double mutation of Q180 and Q207 resulted in minimal change in transport activity when sodium was removed from the uptake medium. We propose that sodium-dependent affinity for carnitine is dependent on sodium recognition by these critical amino acids in hOCTN2, whereas carnitine transport by OCTN2 requires functional linkage between TMD1-7 and TMD11.
More Related Videos
06:18Brain Slice Biotinylation: An Ex Vivo Approach to Measure Region-specific Plasma Membrane Protein Trafficking in Adult Neurons
Published on: April 3, 2014
08:54Monitoring Leucine-Rich Repeat Containing 8 Channel (LRRC8/VRAC) Activity Using Sensitized-Emission Förster Resonance Energy Transfer (SE-FRET)
Published on: August 9, 2024
Related Concept Videos
Membrane Transporters
Transporters are mainly composed of alpha-helices, built from bundles of ten or more helices traversing the plasma membrane. The solute-binding sites are located midway, where some of the helices are broken or distorted, making space for the binding site through...
The Significance of Membrane Transport
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
Secondary Active Transport
Secondary Active Transport
Secondary Active Transport
Protein Transport to the Thylakoids