ABSTRACT
Budding yeast cells multiply by asymmetric cell division. During this process, the cell organelles are transported by myosin motors along the actin cytoskeleton into the growing bud, and, at the same time, some organelles must be retained in the mother cell. The ordered partitioning of organelles depends on highly regulated binding of motor proteins to cargo membranes. To search for novel components involved in this process, we performed a protein fragment complementation screen using the cargo-binding domain of Myo2, the major organelle transporter in yeast, as bait and a genome-wide strain collection expressing yeast proteins as prey. One robust hit was Alo1, a poorly characterized D-arabinono-1,4-lactone oxidase located in the mitochondrial outer membrane. We found that mutants lacking Alo1 exhibited defects in mitochondrial morphology and inheritance. During oxidative stress, dysfunctional mitochondria are immobilized in the mother in wild-type cells. Intriguingly, overexpression of ALO1 restored bud-directed transport of mitochondria under these conditions. We propose that Alo1 supports the recruitment of Myo2 to mitochondria and its activity is particularly important under oxidative stress.
Footnotes
Author contributions
Conceptualization: X.C., T.K., B.W.; Investigation: X.C., N.R., V.B., M.K.; Data curation: X.C., N.R., M.K., T.K., B.W.; Writing – original draft: B.W.; Writing – review and editing: X.C., N.R., V.B., M.K., T.K., B.W.; Supervision: T.K., B.W.; Project administration: B.W.; Funding acquisition: T.K., B.W.
Funding
This work was supported by the Deutsche Forschungsgemeinschaft (433461293 to B.W., 459304237 to T.K.) and the Elitenetzwerk Bayern through the ‘Biological Physics’ program.
Data availability
All relevant data can be found within the article and its supplementary information.