The TMEM120A or TACAN protein, of 343 aas and 7 TMSs. May function in adipogenesis (Batrakou et al. 2015). TACAN is reported to be a Ca2+-transporting ion channel involved in sensing mechanical pain. It is expressed in a subset of nociceptors in humans, and its heterologous
expression increases mechanically evoked currents in cell lines.
Purification and reconstitution of TACAN in synthetic lipids generates a
functional ion channel that transports Ca2+ (Beaulieu-Laroche et al. 2020). However, Niu et al. 2021 failed to detect the proposed mechanosensitive ion channel activity of TACAN. Using membrane reconstitution methods, they found that TACAN, at high protein concentrations, produces heterogeneous conduction levels that are not mechanosensitive and are most consistent with disruptions of the lipid bilayer. They determined the structure of TACAN using single-particle cryo-EM and observed that it is a symmetrical dimeric transmembrane protein. Each protomer contains an intracellular-facing cleft with a coenzyme A cofactor, confirmed by mass spectrometry. The TACAN protomer is related in three-dimensional structure to a fatty acid elongase, ELOVL7. Thus, TACAN may not be a mechanosensitive ion channel. It may not mediate poking- or stretch-induced channel activities (Rong et al. 2021; Xue et al. 2021).
|Protein Name:||Transmembrane protein 120A|
|Species:||Homo sapiens (Human)  |
|Number of TMSs:||7|
|Location1 / Topology2 / Orientation3:
Nucleus inner membrane1 / Multi-pass membrane protein2
1: MQPPPPGPLG DCLRDWEDLQ QDFQNIQETH RLYRLKLEEL TKLQNNCTSS ITRQKKRLQE
61: LALALKKCKP SLPAEAEGAA QELENQMKER QGLFFDMEAY LPKKNGLYLS LVLGNVNVTL
121: LSKQAKFAYK DEYEKFKLYL TIILILISFT CRFLLNSRVT DAAFNFLLVW YYCTLTIRES
181: ILINNGSRIK GWWVFHHYVS TFLSGVMLTW PDGLMYQKFR NQFLSFSMYQ SFVQFLQYYY
241: QSGCLYRLRA LGERHTMDLT VEGFQSWMWR GLTFLLPFLF FGHFWQLFNA LTLFNLAQDP
301: QCKEWQVLMC GFPFLLLFLG NFFTTLRVVH HKFHSQRHGS KKD