Abstract
Mitochondrial transport is critical for maintenance of normal neuronal function. Here, we identify a novel mitochondria protein, hypoxia up-regulated mitochondrial movement regulator (HUMMR), which is expressed in neurons and is markedly induced by hypoxia-inducible factor 1 alpha (HIF-1alpha). Interestingly, HUMMR interacts with Miro-1 and Miro-2, mitochondrial proteins that are critical for mediating mitochondrial transport. Interestingly, knockdown of HUMMR or HIF-1 function in neurons exposed to hypoxia markedly reduces mitochondrial content in axons. Because mitochondrial transport and distribution are inextricably linked, the impact of reduced HUMMR function on the direction of mitochondrial transport was also explored. Loss of HUMMR function in hypoxia diminished the percentage of motile mitochondria moving in the anterograde direction and enhanced the percentage moving in the retrograde direction. Thus, HUMMR, a novel mitochondrial protein induced by HIF-1 and hypoxia, biases mitochondria transport in the anterograde direction. These findings have broad implications for maintenance of neuronal viability and function during physiological and pathological states.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Animals
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Astrocytes / metabolism
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Axons / metabolism
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Axons / ultrastructure
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Base Sequence
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Biological Transport / physiology
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Cells, Cultured
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Cerebral Cortex / cytology
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Cerebral Cortex / metabolism
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Humans
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Hypoxia / metabolism*
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Hypoxia-Inducible Factor 1, alpha Subunit / genetics
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Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
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Intracellular Signaling Peptides and Proteins
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Mice
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Mice, Transgenic
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Mitochondria / metabolism*
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Mitochondria / ultrastructure
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Mitochondrial Proteins / genetics
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Mitochondrial Proteins / metabolism*
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Molecular Sequence Data
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Multiprotein Complexes / metabolism
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism
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Neurons / metabolism
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rho GTP-Binding Proteins / genetics
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rho GTP-Binding Proteins / metabolism
Substances
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Carrier Proteins
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FIS1 protein, human
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Hypoxia-Inducible Factor 1, alpha Subunit
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Intracellular Signaling Peptides and Proteins
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Membrane Proteins
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Mitochondrial Proteins
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Multiprotein Complexes
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Nerve Tissue Proteins
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TRAK2 protein, human
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RHOT1 protein, human
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RHOT2 protein, human
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rho GTP-Binding Proteins