Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.4.24.64 (
MPP
)
1,876
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Polynucleotide phosphorylase
(
PNPase
) is an exoribonuclease and poly(A) polymerase postulated to function in the cytosol and mitochondrial matrix. Prior overexpression studies resulted in
PNPase
localization to both the cytosol and mitochondria, concurrent with cytosolic RNA degradation and pleiotropic cellular effects, including growth inhibition and apoptosis, that may not reflect a physiologic role for endogenous
PNPase
. We therefore conducted a mechanistic study of
PNPase
biogenesis in the mitochondrion. Interestingly,
PNPase
is localized to the intermembrane space by a novel import pathway.
PNPase
has a typical N-terminal targeting sequence that is cleaved by the
matrix processing peptidase
when
PNPase
engaged the TIM23 translocon at the inner membrane. The i-AAA protease Yme1 mediated translocation of
PNPase
into the intermembrane space but did not degrade
PNPase
. In a yeast strain deleted for Yme1 and expressing
PNPase
, nonimported
PNPase
accumulated in the cytosol, confirming an in vivo role for Yme1 in
PNPase
maturation.
PNPase
localization to the mitochondrial intermembrane space suggests a unique role distinct from its highly conserved function in RNA processing in chloroplasts and bacteria. Furthermore, Yme1 has a new function in protein translocation, indicating that the intermembrane space harbors diverse pathways for protein translocation.
...
PMID:A new function in translocation for the mitochondrial i-AAA protease Yme1: import of polynucleotide phosphorylase into the intermembrane space. 1696 79
