RESUMO
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.
Assuntos
Mitocôndrias/metabolismo , Cadeias Pesadas de Miosina/metabolismo , Miosina Tipo V/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Actinas/metabolismo , Sequência de Bases , Divisão Celular , DNA Fúngico/genética , Deleção de Genes , Genes Fúngicos , Mitocôndrias/ultraestrutura , Mutação , Cadeias Pesadas de Miosina/genética , Miosina Tipo V/genética , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Proteínas rab de Ligação ao GTP/genéticaRESUMO
We describe a method for segmenting arterial vessel wall motion to sub-pixel resolution, using the returns from M-mode ultrasound. The technique involves measuring the spatial offset between all pairs of scans from their cross-correlation, converting the spatial offsets to relative wall motion through a global optimization, and finally translating from relative to absolute wall motion by interpolation over the M-mode image. The resulting detailed wall distension waveform has the potential to enhance existing vascular biomarkers, such as strain and compliance, as well as enable new ones.