A type V myosin (Myo2p) and a Rab-like G-protein (Ypt11p) are required for retention of newly inherited mitochondria in yeast cells during cell division.
Two actin-dependent force generators contribute to mitochondrial inheritance: Arp2/3 complex and the myosin V Myo2p (together with its Rab-like binding partner Ypt11p). We found that deletion of YPT11, reduction of the length of the Myo2p lever arm (myo2-Delta6IQ), or deletion of MYO4 (the other yeast myosin V), had no effect on mitochondrial morphology, colocalization of mitochondria with actin cables, or the velocity of bud-directed mitochondrial movement. In contrast, retention of mitochondria in the bud was compromised in YPT11 and MYO2 mutants. Retention of mitochondria in the bud tip of wild-type cells results in a 60% decrease in mitochondrial movement in buds compared with mother cells. In ypt11Delta mutants, however, the level of mitochondrial motility in buds was similar to that observed in mother cells. Moreover, the myo2-66 mutant, which carries a temperature-sensitive mutation in the Myo2p motor domain, exhibited a 55% decrease in accumulation of mitochondria in the bud tip, and an increase in accumulation of mitochondria at the retention site in the mother cell after shift to restrictive temperatures. Finally, destabilization of actin cables and the resulting delocalization of Myo2p from the bud tip had no significant effect on the accumulation of mitochondria in the bud tip.
Boldogh
Istvan R
IR
Department of Anatomy and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
Ramcharan
Sharmilee L
SL
Yang
Hyeong-Cheol
HC
Pon
Liza A
LA
D000199:Actins / Q000378:metabolism; D001483:Base Sequence; D002455:Cell Division; D004271:DNA, Fungal / Q000235:genetics; D017353:Gene Deletion; D005800:Genes, Fungal; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D009154:Mutation; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism*; D024701:Myosin Type V / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
D000199:Actins; D004271:DNA, Fungal; C077512:MYO2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C468556:Ypt11 protein, S cerevisiae; D024701:Myosin Type V; D018995:Myosin Heavy Chains; D020691:rab GTP-Binding Proteins