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This article discusses a study that used super-resolution microscopy to examine the organization of apical junctions in intestinal epithelia. The researchers found that there is a two-layered structure to the junctions, with distinct zones for E-cadherin/catenin and Nectin/Afadin/Actin. This segregation was observed both in vivo and in vitro. The findings challenge the previous understanding of cell-cell junctions and provide new insights into their organization. The study also highlights the role of Afadin in generating appropriate apical tension and force transmission between cells. The findings have implications for understanding cell adhesion and tissue remodeling processes. [Extracted from the article]

Restricting centriole duplication to once per cell cycle is critical for chromosome segregation and genomic stability, but the mechanisms underlying this block to reduplication are unclear. Genetic analyses have suggested an involvement for Skp/Cullin/F box (SCF)-class ubiquitin ligases in this process. In this study, we describe a mechanism to prevent centriole reduplication in Drosophila melanogaster whereby the SCF E3 ubiquitin ligase in complex with the F-box protein Slimb mediates proteolytic degradation of the centrosomal regulatory kinase Plk4. We identified [SCF.sup.Slimb] as a regulator of centriole duplication via an RNA interference (RNAi) screen of Cullin-based ubiquitin ligases. We found that Plk4 binds to Slimb and is an [SCF.sup.Slimb] target. Both Slimb and Plk4 localize to centrioles, with Plk4 levels highest at mitosis and absent during S phase. Using a Plk4 Slimb-binding mutant and Slimb RNAi, we show that Slimb regulates Plk4 localization to centrioles during interphase, thus regulating centriole number and ensuring the block to centriole reduplication.