Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8324679 | The International Journal of Biochemistry & Cell Biology | 2012 | 11 Pages |
Abstract
Mitochondrial morphology is dynamic and controlled by coordinated fusion and fission pathways. The role of mitochondrial chaperones in mitochondrial morphological changes and pathology is currently unclear. Here we report that altered levels of DnaJA3 (Tid1/mtHsp40) a mitochondrial member of the DnaJ protein family, and heat shock protein (Hsp) co-chaperone of matrix 70Â kDa Hsp70 (mtHsp70/mortalin/HSPA9), induces mitochondrial fragmentation. Suppression of DnaJA3 induced mitochondrial fragmentation in HeLa cells. Elevated levels of DnaJA3 in normal Hs68 fibroblast cells and HeLa, SKN-SH, U87 and U251 cancer cell lines induces mitochondrial fragmentation. Mitochondrial fragmentation induction was not observed in HeLa cells when other DnaJA family members, or mitochondrial DnaJ protein HSC20, were ectopically expressed, indicating that the effects on mitochondrial morphology were specific to DnaJA3. We show that the DnaJ domain (amino acids 88-168) of DnaJA3 is sufficient for the induction of mitochondrial fragmentation. Furthermore, an H121Q point mutation of the DnaJ domain, which abrogates interaction and activation of mtHsp70 ATPase, eliminates fragmentation induced by DnaJA3. This suggests that DnaJA3 interaction with mtHsp70 may be critical in mitochondrial morphological changes. DnaJA3-induced mitochondrial fragmentation was dependent on fission factor dynamin-related protein 1 (Drp1). Ectopic expression of the mitofusins (Mfn1 and Mfn2), however, does not rescue DnaJA3-induced mitochondrial fragmentation. Lastly, elevated levels of DnaJA3 inducing mitochondrial fragmentation were associated with reduction in cell viability. Taken together, elevated DnaJA3 induces Drp1-depedendent mitochondrial fragmentation and decreased cell viability.
Keywords
MFN2HBSSHspRIPADrp1Mfn1TOM20Aco1antimycin ACCCPTMRMCOXIVDsRed2TIM23Tim44tetramethyl rhodamine methyl esterDiscosoma sp. Red fluorescent proteinPAGEPRSeGFPSDSMitochondrial DNAGLT1opa1MOIshort interfering RNAROSsiRNAoptic atrophy 1aconitasepolyacrylamide gel electrophoresisstandard deviationradioimmunoprecipitation bufferMitochondrial fragmentationmtDNAsodium dodecyl sulfateHank's buffered salt solutionmitofusin 1mitofusin 2polymerase chain reactionPCRHeat shock proteinenhanced green fluorescent proteindynamin-related protein 1multiplicity of infectionglutamate synthaseReactive oxygen species
Related Topics
Life Sciences
Biochemistry, Genetics and Molecular Biology
Biochemistry
Authors
Adam N. Elwi, Byoungchun Lee, H. Christopher Meijndert, Janice E.A. Braun, Sung-Woo Kim,