hERK1 signaling complexes in mitochondria from HeLa cells.

GST-hERK1 or GST-null recombinant proteins immobilized on GSH-agarose were incubated overnight with mitochondrial extracts. Beads were extensively washed and eluted proteins run on PAGE-SDS. Proteins were stained with Coomasie Brilliant Blue G-250 (Fig. 2). A sample of each band in the GST-hERK1 or GST-null lane was excised and analyzed by mass spectrometry for protein identification. Only proteins present in GST-hERK but not in GST-null precipitates were considered as specific ERK partners. *Also confirmed by LC-MS/MS. (#)Numbers in superscript correspond to the numbering of protein bands in Fig. 2. Only ERK interaction partners that were extensively corroborated by further experiments are shown. For the totality of ERK interaction partners recovered after GST-hERK1 pulldown and MALDI-TOF identification refer to supplemental Table S2 and Supporting Information S1.