TUE-CMS

Abstract:Lipid droplets (LDs), reservoirs of cholesterols and fats, are organelles that hydrolyse lipids in the cell. In zebrafish embryos, the actomyosin complex and filamentous microtubules control the periodic regulation of the LD geometry. Contrary to the existing hypothesis that LD transport involves the kinesin-microtubule system, we find that their recruitment to the blastodisc depends on the actomyosin turnover and is independent of the microtubules.The early zebrafish embryonic development involves interesting dynamics and migration pattern of LDs. We show that lipolysis is one of the crucial factors that power the early growth of the zebrafish embryo. The lipolysis alters the lipid content and the shape-and-size of LDs. We find two distinct geometrical states of LDs, an inactive and an active state, that occur periodically. The actomyosin and microtubules jointly control the alteration of the LD geometry. Contrary to the existing hypothesis that LD transport involves the kinesin, we find that in zebrafish embryos, the recruitment of LDs to the blastodisc is independent of the microtubules. Additionally, we show that the LDs provide defense against starvation and microbe-infection. Our findings demonstrate the importance of LDs in development of the zebrafish embryos. The alterations in LDs geometry suggests new mechanisms associated with specific functions of LDs, such as their storage capacity for fats or proteins etc.