TY  - JOUR
A1  - Kato, Hiroki
A1  - Lu, Qiping
A1  - Rapaport, Doron
A1  - Kozjak-Pavlovic, Vera
T1  - Tom70 Is Essential for PINK1 Import into Mitochondria
JF  - PLoS ONE
N2  - PTEN induced kinase 1 (PINK1) is a serine/threonine kinase in the outer membrane of mitochondria (OMM), and known as a responsible gene of Parkinson's disease (PD). The precursor of PINK1 is synthesized in the cytosol and then imported into the mitochondria via the translocase of the OMM (TOM) complex. However, a large part of PINK1 import mechanism remains unclear. In this study, we examined using cell-free system the mechanism by which PINK1 is targeted to and assembled into mitochondria. Surprisingly, the main component of the import channel, Tom40 was not necessary for PINK1 import. Furthermore, we revealed that the import receptor Tom70 is essential for PINK1 import. In addition, we observed that although PINK1 has predicted mitochondrial targeting signal, it was not processed by the mitochondrial processing peptidase. Thus, our results suggest that PINK1 is imported into mitochondria by a unique pathway that is independent of the TOM core complex but crucially depends on the import receptor Tom70.
KW  - binding
KW  - outer-membrane proteins
KW  - Parkinsons diesease
KW  - intracellular membranes
KW  - quality control
KW  - pathway
KW  - recruitment
KW  - biogenesis
KW  - mechanisms
KW  - complex
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131061
VL  - 8
IS  - 3
ER  - 
TY  - JOUR
A1  - Ioakeimidis, Fotis
A1  - Ott, Christine
A1  - Kozjak-Pavlovic, Vera
A1  - Violitzi, Foteini
A1  - Rinotas, Vagelis
A1  - Makrinou, Eleni
A1  - Eliopoulos, Elias
A1  - Fasseas, Costas
A1  - Kollias, George
A1  - Douni, Eleni
T1  - A Splicing Mutation in the Novel Mitochondrial Protein DNAJC11 Causes Motor Neuron Pathology Associated with Cristae Disorganization, and Lymphoid Abnormalities in Mice
JF  - PLOS ONE
N2  - Mitochondrial structure and function is emerging as a major contributor to neuromuscular disease, highlighting the need for the complete elucidation of the underlying molecular and pathophysiological mechanisms. Following a forward genetics approach with N-ethyl-N-nitrosourea (ENU)-mediated random mutagenesis, we identified a novel mouse model of autosomal recessive neuromuscular disease caused by a splice-site hypomorphic mutation in a novel gene of unknown function, DnaJC11. Recent findings have demonstrated that DNAJC11 protein co-immunoprecipitates with proteins of the mitochondrial contact site (MICOS) complex involved in the formation of mitochondrial cristae and cristae junctions. Homozygous mutant mice developed locomotion defects, muscle weakness, spasticity, limb tremor, leucopenia, thymic and splenic hypoplasia, general wasting and early lethality. Neuropathological analysis showed severe vacuolation of the motor neurons in the spinal cord, originating from dilatations of the endoplasmic reticulum and notably from mitochondria that had lost their proper inner membrane organization. The causal role of the identified mutation in DnaJC11 was verified in rescue experiments by overexpressing the human ortholog. The full length 63 kDa isoform of human DNAJC11 was shown to localize in the periphery of the mitochondrial outer membrane whereas putative additional isoforms displayed differential submitochondrial localization. Moreover, we showed that DNAJC11 is assembled in a high molecular weight complex, similarly to mitofilin and that downregulation of mitofilin or SAM50 affected the levels of DNAJC11 in HeLa cells. Our findings provide the first mouse mutant for a putative MICOS protein and establish a link between DNAJC11 and neuromuscular diseases.
KW  - dominant optic atrophy
KW  - amyotrophic-lateral-sclerosis
KW  - nervous system
KW  - membrane organization
KW  - mitofilin
KW  - data-bank
KW  - model
KW  - biogenesis
KW  - morphology
KW  - reveals
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-115581
VL  - 9
IS  - 8
ER  -