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:2.4.1.18 (
branching enzyme
)
628
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Misregulation of the E3 ubiquitin ligase Parkin and the kinase
PINK1
underlie both inherited and idiopathic Parkinson's disease-associated neurodegeneration. Parkin and
PINK1
work together to catalyze the assembly of ubiquitin chains on substrates located on the outer mitochondrial membrane to facilitate autophagic removal of damaged mitochondria through a process termed mitophagy. Quantitative measurements of Parkin-mediated chain assembly, both
in vitro
and on mitochondria, have revealed that chains are composed of Lys6, Lys11, Lys48, and Lys63 linkages. The combinatorial nature of these chains is further expanded by the ability of
PINK1
to phosphorylate individual subunits. The precise architecture of chains produced by the coordinated action of
PINK1
and Parkin, however, are unknown. Here, we demonstrate that quantitative middle-down mass spectrometry using uniformly
15
N-labeled ubiquitin variants as internal standards informs on the extent of chain branching. We find that Parkin is a prolific
branching enzyme
in vitro
. Quantitative middle-down mass spectrometry also reveals that phospho-Ser65-ubiquitin (pSer65-Ub)-a key activator of Parkin-is not incorporated into chains to a significant extent. Our results suggest that Parkin-mediated chain branching is "on-pathway", and branch points are the principal targets of the deubiquitinase USP30.
...
PMID:Quantitative Middle-Down MS Analysis of Parkin-Mediated Ubiquitin Chain Assembly. 3229 15
