NMR studies on the interactions between yeast Vta1 and Did2 during the multivesicular bodies sorting pathway

Preserving Genome Integrity: Unveiling the Roles of ESCRT Machinery

The endosomal sorting complex required for transport (ESCRT) machinery is composed of an articulated architecture of proteins that assemble at multiple cellular sites. The ESCRT machinery is involved in pathways that are pivotal for the physiology of the cell, including vesicle transport, cell division, and membrane repair. The subunits of the ESCRT I complex are mainly responsible for anchoring the machinery to the action site. The ESCRT II subunits function to bridge and recruit the ESCRT III subunits. The latter are responsible for finalizing operations that, independently of the action site, involve the repair and fusion of membrane edges. In this review, we report on the data related to the activity of the ESCRT machinery at two sites: the nuclear membrane and the midbody and the bridge linking cells in the final stages of cytokinesis. In these contexts, the machinery plays a significant role for the protection of genome integrity by contributing to the control of the abscission checkpoint and to nuclear envelope reorganization and correlated resilience. Consistently, several studies show how the dysfunction of the ESCRT machinery causes genome damage and is a codriver of pathologies, such as laminopathies and cancer.

Vps60 initiates alternative ESCRT-III filaments

Endosomal sorting complex required for transport-III (ESCRT-III) participates in essential cellular functions, from cell division to endosome maturation. The remarkable increase of its subunit diversity through evolution may have enabled the acquisition of novel functions. Here, we characterize a novel ESCRT-III copolymer initiated by Vps60. Membrane-bound Vps60 polymers recruit Vps2, Vps24, Did2, and Ist1, as previously shown for Snf7. Snf7- and Vps60-based filaments can coexist on membranes without interacting as their polymerization and recruitment of downstream subunits remain spatially and biochemically separated. In fibroblasts, Vps60/CHMP5 and Snf7/CHMP4 are both recruited during endosomal functions and cytokinesis, but their localization is segregated and their recruitment dynamics are different. Contrary to Snf7/CHMP4, Vps60/CHMP5 is not recruited during nuclear envelope reformation. Taken together, our results show that Vps60 and Snf7 form functionally distinct ESCRT-III polymers, supporting the notion that diversification of ESCRT-III subunits through evolution is linked to the acquisition of new cellular functions.

Enhanced β-carotene production by overexpressing the DID2 gene, a subunit of ESCRT complex, in engineered Yarrowia lipolytica

OBJECTIVE

β-Carotene has been widely used in the food and feed industry and has significant commercial value. This study aimed to increase the β-carotene production in engineered Yarrowia lipolytica by optimizing the host metabolic network. The DID2 gene, a subunit of the endosomal sorting complex required for transport (ESCRT), was integrated into a β-carotene producing strain.

RESULTS

The β-carotene production was increased by 260%, and the biomass increased by 10% for engineered Y. lipolytica. Meanwhile, DID2 elevated the mRNA level and protein level of the genes in the β-carotene synthesis pathway, then increased precursors (FPP, Lycopene) utilization. DID2 also increased the mRNA level of the genes in the glucose pathway, pentose phosphate pathway, and tricarboxylic acid cycle and promoted glucose utilization and cofactors consumption.

CONCLUSION

The ESCRT protein complex subunit, DID2, improved β-carotene production in engineered Y. lipolytica and beneficial to glucose utilization and cofactors consumption. This study provided new finding of the DID2 gene's function and it mostly could be used for many other natural product productions.