hERK1 with Mitochondria. Homo sapiens

Extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) are members of the MAPK family and participate in the transduction of stimuli in cellular responses. Their long-term actions are accomplished by promoting the expression of specific genes whereas faster responses are achieved by direct phosphorylation of downstream effectors located throughout the cell. Here, we determined that hERK1 translocates into the mitochondria of HeLa cells upon a proliferative stimulus. In that environment, hERK1 physically associates with (i) at least 5 known mitochondrial proteins with functions related to transport, signalling, and metabolism; (ii) histones H2A and H4; and (iii) other cytosolic proteins. This work indicates for the first time the presence of diverse ERKcomplexes in mitochondria and thus provides a new perspective for assessing the functions of ERK1 in the regulation of cellular signalling and trafficking. We propose that ERK may act as a carrier protein, bringing histones into close proximity with mitochondrial enriched ATP surroundings and assisting their translocation to the nucleus, where ERK-histone complexes may act upon gene transcription. Furthermore, histones may sense the status of energetic metabolism and relay the information to the nuclei so as to influence cell division. Overall design: Dye-Swap Design ERK vs. Control (3+3 Replicates)