Related Experiment Video
Updated: Jun 17, 2026

X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
Mitochondrial processing peptidase activity is controlled by the processing of alpha-MPP during development in
Koki Nagayama1,2, Tetsuo Ohmachi1
1Department of Biochemistry and Biotechnology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, 036-8561, Japan.
Abstract:
We investigated the expression of the alpha subunit of the Dictyostelium mitochondrial processing peptidase (Ddalpha-MPP) during development. Ddalpha-MPP mRNA is expressed at the highest levels in vegetatively growing cells and during early development, and is markedly downregulated after 10 h of development. The Ddalpha-MPP protein is expressed as two forms, designated alpha-MPP(H) and alpha-MPP(L), throughout the Dictyostelium life cycle. The larger form, alpha-MPP(H), is cleaved to produce the functional alpha-MPP(L) form. We were not able to isolate mutants in which the alpha-mpp gene had been disrupted. Instead, an antisense transformant, alphaA2, expressing alpha-MPP at a lower level than the wild-type AX-3 was isolated to examine the function of the alpha-MPP protein. Development of the alphaA2 strain was normal until the slug formation stage, but the slug stage was prolonged to approximately 24 h. In this prolonged slug stage, only alpha-MPP(H) was present, and alpha-MPP(L) protein and MPP activity were not detected. After 28 h, alpha-MPP(L) and MPP activity reappeared, and normal fruiting bodies were formed after a delay of approximately 8 h compared with normal development. These results indicate that MPP activity is controlled by the processing of alpha-MPP(H) to alpha-MPP(L) during development in Dictyostelium.
Related Concept Videos
Translocation of Proteins into the Mitochondria
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Mitochondrial Precursor Proteins
Most of the mitochondrial precursors...
Mitochondrial Protein Sorting
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
Energy to Drive Translocation
Generally, polypeptides are unfolded by two distinct...
Role of Matrix Metalloproteases in Degradation of ECM
A...
Structure of Porins

