Evidence for mitochondrial Lonp1 expression in the nucleus
Lara Gibellini, Rebecca Borella, Anna De Gaetano, Giada Zanini, Domenico Lo Tartaro, Gianluca Carnevale, Francesca Beretti, Lorena Losi, Sara De Biasi, Milena Nasi, Mattia Forcato, Andrea Cossarizza, Marcello Pinti
Abstract
The coordinated communication between the mitochondria and nucleus is essential for cellular activities. Nonetheless, the pathways involved in this crosstalk are scarcely understood. The protease Lonp1 was previously believed to be exclusively located in the mitochondria, with an important role in mitochondrial morphology, mtDNA maintenance, and cellular metabolism, in both normal and neoplastic cells. However, we recently detected Lonp1 in the nuclear, where as much as 22% of all cellular Lonp1 can be found. Nuclear localization is detectable under all conditions, but the amount is dependent on a response to heat shock (HS). Lonp1 in the nucleus interacts with heat shock factor 1 (HSF1) and modulates the HS response. These findings reveal a novel extramitochondrial function for Lonp1 in response to stress.