Page 4 - E. Cell adhesion and cytoskeletal dynamics

[E. Cell adhesion and cytoskeletal dynamics-3]

Cytoskeleton Dependent Activation of Tentonin

3/TMEM150C, an Essential Component of Mechanosensitive

Channel

Sungmin Pak¹, Gyu-Sang Hong¹, Hyungsup Kim¹, Jaehyouk Choi¹, Huanjun Lu¹, Kyungmin Kim¹, Hyesu

Kim¹, Luan Nguyen Thien¹, Taewoong Ha¹, Sujin Lim¹, Mi-Sun Kim¹, Uhtaek Oh¹

¹Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea

Tentonin 3/TMEM150C (TTN3) has been recently discovered as a novel mechanosensitive (MS) channel candidate.

It is activated by mechanical stimuli followed by slow inactivation in the heterologous system, distinct from Piezo1
or 2 that has a rapid inactivation. However, the activation mechanism of TTN3 has been challenged. Because TTN3

fails to show MS currents in Piezo1-deficient HEK (HEK-P1KO) cells, TTN3 is considered to be a regulatory protein
controlling Piezo1 activity. To address this issue, we hypothesized that mechanosensitivity of TTN3 depends on the

cytoskeleton integrity of the cell. Here, we found that loss of TTN3 MS current in HEK-P1KO is highly correlated
with the focal adhesion (FA) complex. When the F-actin assembly is strengthened after jasplakinolide-treatment,

mechanical stimuli robustly evoked MS currents in Ttn3-transfected HEK-P1KO cells. HEK-P1KO cells showed
dramatic loss of FA proteins and knockdown of FA proteins in HEK cells also reduced the TTN3-dependent MS

currents. Thus, we conclude that mechanosensitivity of TTN3 is dependent on the cytoskeleton integrity. This finding
supports the idea that TTN3 is an essential component of the slowly inactivating MS channel complex.