Spatial Distribution of
Cellular Function: The Partitioning of Proteins between Mitochondria
and the Nucleus in MCF7 Breast Cancer Cells
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Abstract
Concurrent proteomics analysis of the nuclei and mitochondria
of MCF7 breast cancer cells identified 985 proteins (40% of all detected
proteins) present in both organelles. Numerous proteins from all five
complexes involved in oxidative phosphorylation (e.g., NDUFA5, NDUFB10,
NDUFS1, NDUF2, SDHA, UQRB, UQRC2, UQCRH, COX5A, COX5B, MT-CO2, ATP5A1,
ATP5B, ATP5H, etc.), from the TCA-cycle (DLST, IDH2, IDH3A, OGDH,
SUCLAG2, etc.), and from glycolysis (ALDOA, ENO1, FBP1, GPI, PGK1,
TALDO1, etc.) were distributed to both the nucleus and mitochondria.
In contrast, proteins involved in nuclear/mitochondrial RNA processing/translation
and Ras/Rab signaling showed different partitioning patterns. The
identity of the OxPhos, TCA-cycle, and glycolysis proteins distributed
to both the nucleus and mitochondria provides evidence for spatio-functional
integration of these processes over the two different subcellular
organelles. We suggest that there are unrecognized aspects of functional
coordination between the nucleus and mitochondria, that integration
of core functional processes via wide subcellular distribution of
constituent proteins is a common characteristic of cells, and that subcellular spatial integration of function may be a vital aspect of cancer