Mateska et al. describe a mechanism restricting the range of SHH pathway activation in adrenal gland to cells with ARL13B-positive primary cilia that are in physical contact with SHH-producing cells. Cancerous adrenocortical cells evade this restriction by ectopically activating SHH targets in response to TGF-β.
Hebbar et al. examine morphogenesis of the apical photosensitive plasma membrane of Drosophila photoreceptors. Using mutants exhibiting growth defects, they identify hydroxylated sphingolipid biosynthesis as a regulator of rhabdomere growth. Hydroxylated sphingolipids regulate Rab11-mediated trafficking of Rhodopsin, a major structural component of rhabdomeres.
Endicott et al. report that inhibition of class I PI3K activates chaperone-mediated autophagy (CMA) in cultured cells and mice. Selective inhibition of class III PI3K does not activate CMA. This work disentangles previously misunderstood roles of PI3Ks in CMA regulation.
How cells respond to deleterious effects imposed by disrupted nuclear pore complex (NPC) assembly is not well defined. Lord and Wente demonstrate that nuclear envelope–vacuole interactions expand in response to perturbed NPC assembly to promote viability, nuclear envelope remodeling, and proper NPC biogenesis.
The EB1–Kinesin-14 complex is required for efficient metaphase spindle assembly and kinetochore bi-orientation
Kornakov et al. investigate mechanisms of bipolar spindle assembly, a critical prerequisite for accurate chromosome segregation in mitosis. They define the molecular organization of an interaction interface between the conserved microtubule plus-end tracking protein EB1 and the minus-end motor Kinesin-14 and demonstrate with specific mutations that this complex is required for proper organization of the metaphase spindle.
Dendrite pathology is a prominent early feature of neurodegenerative diseases. Using dendritic arborization neurons of Drosophila, Han et al. show that Relish/NF-κB contributes to dendrite and behavioral defects in animal models for polyglutamine diseases and amyotrophic lateral sclerosis via transcriptionally upregulating Tup.
NuMA disruption causes nuclear defects, and it was unclear if this is due to NuMA's essential spindle function. Serra-Marques et al. show that NuMA keeps chromosomes together at nuclear formation and promotes a mechanically robust nucleus independently of its spindle function.
Meiotic anaphase has been reported to be mediated by kinetochore-independent pushing forces in C. elegans. Danlasky et al. find that depletion of kinetochore proteins reduces pulling forces and prevents successful separation of homologous chromosomes during C. elegans meiosis.
Koyama-Honda et al. developed high-speed single-molecule imaging and found that CD59 clusters and GM1 clusters induced in the plasma membrane outer leaflet–generated nanoscale transbilayer rafts, which continually and transiently recruited Lyn and H-Ras in the inner leaflet by cooperative raft–lipid interactions.
Mitochondrial-derived compartments (MDCs) regulate the mitochondrial proteome in response to nutrient stress. English et al. now show that the ERMES complex and the conserved GTPase Gem1 promote MDC biogenesis at sites of contact between the endoplasmic reticulum and mitochondria.
Higgs and colleagues review the emerging field of cytoskeletal lysine acetylation and discuss impacts of actin acetylation on its cytoplasmic and nuclear functions.
Dey and Baum preview work from Velle and Fritz-Laylin, which shows that Naegleria expresses conserved actin nucleators and generates Arp2/3-dependent lamellar protrusions.