In this Report, which replaces the previous retracted version, the authors show that G3BP is an effector of SG assembly, and that Ras signaling contributes to this process by regulating G3BP dephosphorylation.
This study reveals that functional specification and cooperation of ADF isovariants with different pH sensitivities enable the coordination of the actin cytoskeleton with the cytosolic pH gradient to support pollen tube growth.
Retract and Replace
Metastatic spread of ovarian cancer is associated with multicellular spheroids shed from the primary tumor into the peritoneal cavity. Pawar et al. show that overactive matriptase activates a PAR-2/PI3K/Akt/MMP9 signaling axis to enhance spheroid dissemination and metastasis.
Qi et al. report a novel UHRF1 function as a nuclear protein catalyzing EG5 polyubiquitination for proper spindle architecture and faithful genomic transmission, which is independent of its roles in epigenetics and DNA damage repair. These findings reveal a previously unknown mechanism of UHRF1 controlling mitotic spindle architecture and chromosome behavior.
Bourdais et al. reveal that in mouse oocytes, the kinase MRCK, a Cdc42 effector, promotes ring-shaped myosin II activation and membrane bulging over the meiotic spindle and in the sperm fertilization cone. They further show that the MRCK/myosin II pathway promotes spindle rotation for polar body emission and male pronucleus centration.
Melanoma cells exist in a bidirectional communication unit with lesional keratinocytes. In this niche, melanoma cells hijack keratinocyte signaling, causing them to produce promigratory chemokines through the downregulation of keratinocyte desmosomal cadherin Dsg1, leading to increased migration in vitro and an associated epidermal spread in vivo.
During Drosophila border cell migration, the B-type lamin, Lam, maintains nuclear envelope integrity, stabilizes the lead cell protrusion, and promotes cluster invasion between nurse cells. The nucleus may function as a wedge to promote this collective, confined in vivo movement.
Zeng et al. show that sexually dimorphic cholinergic synaptic transmission occurring at neuromuscular junctions in C. elegans is mediated by the sex-differential abundance of CaMKII, leading to sexually dimorphic locomotion behaviors.
Gaspary et al. use a forward genetics approach in yeast to identify two RNA-binding proteins, Rie1 and Sgn1, which form a complex that promotes the meiotic cell fate decision. This complex acts posttranscriptionally to enhance translation of the master transcriptional regulator of meiosis, IME1, under starvation conditions.
Biton et al. elucidate how large secretory vesicles in Drosophila larval salivary glands employ a distinct machinery comprised of branched actin, myosin-II, and BAR-domain proteins to control fusion pore dynamics. This process facilitates a unique mode of exocytosis, which maintains apical membrane homeostasis during secretion.
How human cells sense chromatin bridges to delay completion of cytokinesis (abscission) is unknown. Petsalaki et al. show that Topoisomerase IIα–DNA covalent complexes are formed on “knotted” DNA and promote recruitment of downstream factors to chromatin bridges to activate the abscission checkpoint and prevent chromatin breakage.
δ-Catenin controls astrocyte morphogenesis via layer-specific astrocyte–neuron cadherin interactions
Tan et al. show that δ-catenin, previously thought to be neuron specific, is expressed by astrocytes and required both in astrocytes and neurons to control astrocyte morphogenesis. Furthermore, they provide evidence demonstrating how the cadherin–δ-catenin adhesion complex controls astrocyte morphology in a layer-specific manner.