Hao Bingqing, Beningo Karen A
bioRxiv. 2023 Mar 7:2023.03.06.531406. doi: 10.1101/2023.03.06.531406.
Traction force and mechanosensing (the ability to sense mechanical attributes of the environment) are two important factors used by a cell to modify behavior during migration. Previously it was determined that the calpain small subunit, calpain 4, regulates the production of traction force independent of its proteolytic holoenzyme. A proteolytic enzyme is formed by calpain4 binding to either of its catalytic partners, calpain 1 and 2. To further understand how calpain 4 regulates traction force, we used two-hybrid analysis to identify more components of the traction pathway. We discovered that basigin, an integral membrane protein and a documented matrix-metalloprotease (MMP) inducer binds to calpain 4 in two-hybrid and pull-down assays. Traction force was deficient when basigin was silenced in MEF cells, and defective in substrate adhesion strength. Consistent with Capn4 MEF cells, the cells deficient in basigin responded to localized stimuli. Together these results implicate basigin in the pathway in which calpain 4 regulates traction force independent of the catalytic large subunits.
牵引力和机械传感（感知环境机械属性的能力）是细胞在迁移过程中用于改变行为的两个重要因素。先前已确定钙蛋白酶小亚基钙蛋白酶4可独立于其蛋白水解全酶调节牵引力的产生。钙蛋白酶4与它的催化伙伴钙蛋白酶1和2中的任何一个结合形成一种蛋白水解酶。为了进一步了解钙蛋白酶4如何调节牵引力，我们使用双杂交分析来识别牵引途径的更多成分。我们发现，在双杂交和下拉实验中，一种整合膜蛋白、有记录的基质金属蛋白酶（MMP）诱导剂基底细胞黏附分子与钙蛋白酶4结合。当基底细胞黏附分子在MEF细胞中沉默时，牵引力不足，底物黏附强度有缺陷。与钙蛋白酶4基因敲除的MEF细胞一致，缺乏基底细胞黏附分子的细胞对局部刺激有反应。这些结果共同表明，基底细胞黏附分子参与了钙蛋白酶4独立于催化大亚基调节牵引力的途径。
