People & Ideas
Septins promote macropinosome maturation and traffic to the lysosome by facilitating membrane fusion
How macropinosomes traffic to lysosomes is poorly understood. Dolat and Spiliotis show that septins associate preferentially with mature macropinosomes in a PI(3,5)P2-dependent manner and regulate fluid-phase cargo traffic to lysosomes by promoting macropinosome/endosome fusion.
How CRISPR Cas9–guide RNA complexes navigate the nucleus and interrogate the genome is not well understood. Ma et al. track these complexes in live cells and find that mutations in the guide seed region significantly reduced the complex’s target residence time, with a commensurate impairment of cleavage.
The phosphatase PP2A-B55 plays an important role in temporal control of mitotic exit; yet, how its substrates are recognized and differentially dephosphorylated is not clear. Using phosphoproteomics and kinetic modeling, Cundell et al. identify PP2A-B55 substrates and define a simple electrostatic recognition signal encoding dephosphorylation rate and temporal order during mitotic exit.
Abscission is the last step of cytokinesis, allowing the physical separation of daughter cells at the end of cell division. It has been considered a cell autonomous process, yet Jungas et al. report that Ephrin/Eph signaling controls the completion of abscission.
Multiciliated cell basal bodies align in stereotypical patterns coordinated by the apical cytoskeleton
Herawati et al. developed a long-term and high-resolution live imaging system for cultured mouse tracheal multiciliated cells. Using both experimental and theoretical studies, they reveal the developmental principle of ciliary basal body alignment directed by apical cytoskeletons.
Glial cells help central nervous system injury repair, but this is limited by the failure of newly produced glial cells to differentiate. Here, Losada-Perez et al. identify the NG2-dependent mechanism modulating glial proliferation and differentiation after damage to promote repair, in the central nervous system of Drosophila.
Mason et al. show that RhoA activity is regulated in space and time by a GEF/GAP module that tunes cell behavior and is required for proper tissue folding and shape during Drosophila morphogenesis.
An siRNA screen for ATG protein depletion reveals the extent of the unconventional functions of the autophagy proteome in virus replication
Autophagy-related (ATG) proteins regulate autophagy, but recent work indicates that some also have autophagy-independent roles. Here, Mauthe et al. perform an unbiased siRNA screen to examine the effects of ATG protein depletion on viral replication and demonstrate autophagy-independent functions for ATG13 and FIP200 in the picornaviral life cycle.