8.A.113.1.1
TMEM150c/Tentonin 3 of 249 aas and 6 TMSs.  According to Anderson et al. 2018, it reglulates channels such as Piezo 1 and Piezo 2. According to Hong et al. 2017, it has inherent channel activity, but Ojeda-Alonso et al. 2022 could not demonstrate this, Nevertheless, Pak et al. 2024 showed that tentonin 3 is a pore-forming subunit of a slow inactivation mechanosensitive channel.  They reported that tentonin 3/TMEM150C (TTN3) confers mechanically activating (MA) currents with slow inactivation kinetics in somato- and barosensory neurons. Thus, purified TTN3 proteins incorporated into the lipid bilayer displayed spontaneous and pressure-sensitive channel currents. These MA currents were conserved across vertebrates and differ from Piezo1 in activation threshold and pharmacological response. Deep neural network structure prediction programs coupled with mutagenetic analysis predicted a rectangular-shaped, tetrameric structure with six transmembrane helices and a pore at the inter-subunit center. The putative pore aligned with two helices of each subunit and had constriction sites whose mutations changed the MA currents. These findings suggest that TTN3 is a pore-forming subunit of a distinct slow inactivation MA channel, potentially possessing a tetrameric structure (Pak et al. 2024). It appears that Tentonin 3 may both modify some channels and be one as well. Kang and Lee 2024 have confirmed the ion channel activity of tentonin and examined its structure.