In today’s new issue of JCB, Stewart et al. reveal that, by organizing both the cytoskeleton and intercellular adhesions, nuclear envelope-spanning LINC complexes help balance forces across cells and tissues. As explained in this week’s In Focus, microtubules are disorganized in epidermal cells lacking the inner nuclear membrane LINC complex component SUN2, disrupting desmosomes and causing Sun2 knockout mice to temporarily lose their hair.
O’Regan et al. reveal that the mitotic kinase Nek6 targets the chaperone Hsp72 to the mitotic spindle, where it promotes the formation of stable K-fibers, the stable microtubule bundles that connect chromosomes to the spindle poles. And, elsewhere in this issue, Prosser et al. demonstrate that the related kinase Nek5 regulates the timing of centrosome separation, another process that orchestrates spindle assembly in mitosis.
Cheng et al. demonstrate that autophagosomes fuse with late endosomes in axonal terminals, a process that allows them to acquire the dynein motors they need to undergo retrograde transport and deliver their contents to lysosomes in the neuronal cell body. More here.
Meanwhile, Pereyra Gerber et al. reveal that the endosomal trafficking protein Rab27a supports HIV-1 replication by promoting production of the phospholipid PI(4,5)P2 at the plasma membrane of infected cells. As explained here, Rab27a promotes delivery of the late endosome-associated lipid kinase PI4KIIa to the plasma membrane, generating specialized PI(4,5)P2-enriched domains that can recruit the viral assembly protein Gag.
And Grikscheit et al. describe how, in breast epithelial cells cultured in 3D, the formin protein FMNL2 stimulates actin filament assembly at intercellular adhesions downstream of the small GTPase Rac1. Senior author Robert Grosse describes his lab’s results in this month’s biosights video podcast, which you can watch below, or download from iTunes.
That’s all for today, but you can find all of the latest papers published in JCB on our table of contents page here.
Cover image of autophagic vacuoles in the neurites of a dorsal root ganglion neuron © 2015 Cheng et al.