Pink1 forms a multiprotein complex with Miro and Milton, linking Pink1 function to mitochondrial trafficking.
Recessive mutations in Pink1 lead to a selective degeneration of dopaminergic neurons in the substantia nigra that is characteristic of Parkinson disease. Pink1 is a kinase that is targeted in part to mitochondria, and loss of Pink1 function can alter mitochondrial morphology and dynamics, thus supporting a link between mitochondrial dysfunction and Parkinson disease etiology. Here, we report the unbiased identification and confirmation of a mitochondrial multiprotein complex that contains Pink1, the atypical GTPase Miro, and the adaptor protein Milton. Our screen also identified an interaction between Pink1 and Mitofilin. Based on previously established functions for Miro and Milton in the trafficking of mitochondria along microtubules, we postulate here a role for Pink1 in mitochondrial trafficking. Using subcellular fractionation, we show that the overexpression of Miro and Milton, both of which are known to reside at the outer mitochondrial membrane, increases the mitochondrial Pink1 pool, suggesting a function of Pink1 at the outer membrane. Further, we document that Pink1 expressed without a mitochondrial targeting sequence can still be targeted to a mitochondria-enriched subcellular fraction via Miro and Milton. The latter finding is important for the interpretation of a previously reported protective effect of Pink1 expressed without a mitochondrial targeting sequence. Finally, we find that Miro and Milton expression suppresses altered mitochondrial morphology induced by loss of Pink1 function in cell culture. Our findings suggest that Pink1 functions in the trafficking of mitochondria in cells.
Weihofen
Andreas
A
Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
Thomas
Kelly Jean
KJ
Ostaszewski
Beth L
BL
Cookson
Mark R
MR
Selkoe
Dennis J
DJ
D000818:Animals; D001692:Biological Transport; D015153:Blotting, Western; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D000099202:PTEN-Induced Putative Kinase
D049452:Green Fluorescent Proteins; D024101:Mitochondrial Proteins; D046912:Multiprotein Complexes; D009124:Muscle Proteins; D011494:Protein Kinases; D011993:Recombinant Fusion Proteins; D020741:rho GTP-Binding Proteins; D000099202:PTEN-Induced Putative Kinase; C088548:IMMT protein, human; C473125:RHOT2 protein, human