Primo Cecilia, Navarre Catherine, Chaumont François, André Bruno
Molecular Physiology of the Cell, Université Libre de Bruxelles (ULB), Biopark, B-6041 Gosselies, Belgium.
Louvain Institute of Biomolecular Science and Technology, UCLouvain, B-1348 Louvain-la-Neuve, Belgium.
iScience. 2022 Apr 11;25(5):104238. doi: 10.1016/j.isci.2022.104238. eCollection 2022 May 20.
The TORC1 (Target of Rapamycin Complex 1) kinase complex plays a pivotal role in controlling cell growth in probably all eukaryotic species. The signals and mechanisms regulating TORC1 have been intensely studied in mammals but those of fungi and plants are much less known. We have previously reported that the yeast plasma membrane H-ATPase Pma1 promotes TORC1 activation when stimulated by cytosolic acidification or nutrient-uptake-coupled H influx. Furthermore, a homologous plant H-ATPase can substitute for yeast Pma1 to promote this H-elicited TORC1 activation. We here report that TORC1 activity in BY-2 cells is also strongly influenced by the activity of plasma membrane H-ATPases. In particular, stimulation of H-ATPases by fusicoccin activates TORC1, and this response is also observed in cells transferred to a nutrient-free and auxin-free medium. Our results suggest that plant H-ATPases, known to be regulated by practically all factors controlling cell growth, contribute to TOR signaling.
雷帕霉素靶蛋白复合体1（TORC1）激酶复合体在几乎所有真核生物物种中对细胞生长的控制起着关键作用。调节TORC1的信号和机制在哺乳动物中已得到深入研究，但在真菌和植物中却知之甚少。我们之前报道过，酵母质膜H⁺-ATP酶Pma1在受到胞质酸化或营养物质摄取偶联的H⁺内流刺激时会促进TORC1的激活。此外，一种同源的植物H⁺-ATP酶可以替代酵母Pma1来促进这种H⁺引发的TORC1激活。我们在此报道，BY-2细胞中的TORC1活性也受到质膜H⁺-ATP酶活性的强烈影响。特别是，壳梭孢菌素对H⁺-ATP酶的刺激会激活TORC1，并且在转移到无营养和无生长素培养基中的细胞中也观察到这种反应。我们的结果表明，已知受几乎所有控制细胞生长的因素调节的植物H⁺-ATP酶有助于TOR信号传导。
