NOA1, a novel ClpXP substrate, takes an unexpected nuclear detour prior to mitochondrial import.

ABSTRACT: The mitochondrial matrix GTPase NOA1 is a nuclear encoded protein, essential for mitochondrial protein synthesis, oxidative phosphorylation and ATP production. Here, we demonstrate that newly translated NOA1 protein is imported into the nucleus, where it localizes to the nucleolus and interacts with UBF1 before nuclear export and import into mitochondria. Mutation of the nuclear localization signal (NLS) prevented both nuclear and mitochondrial import while deletion of the N-terminal mitochondrial targeting sequence (MTS) or the C-terminal RNA binding domain of NOA1 impaired mitochondrial import. Absence of the MTS resulted in accumulation of NOA1 in the nucleus and increased caspase-dependent apoptosis. We also found that export of NOA1 from the nucleus requires a leptomycin-B sensitive,

SUBMITTER: Al-Furoukh N 

PROVIDER: S-EPMC4114565 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature