Time for a quick roundup of some of the highlights from the latest issue of JCB…
Our In Focus paper this week is by Haynes et al., who reveal that a protein called GMFβ helps disassemble the branched actin networks generated by the Arp2/3 complex at the leading edge of migrating fibroblasts, thus promoting lamellipodial retraction and the cells’ ability to navigate towards adhesive directional cues.
Amano et al. describe a novel method to identify the substrates of protein kinases. Kinase-Interacting Substrate Screening, or KISS, allowed the researchers to identify both known and unknown targets of several protein kinases. For example, the researchers identified 356 Rho kinase phosphorylation sites on 140 different proteins, including the polarity protein Scrib, which subsequently forms a ternary complex with Rho kinase and the actin-binding protein Shroom2 in order to promote actomyosin contraction at the free edges of epithelial cells. More here.
Seybold et al. describe how three proteins interact to form a structure that initiates the duplication of spindle pole bodies (SPBs), the yeast equivalent of centrosomes. Kar1, Sfi1, and the centrin homolog Cdc31 are all components of the SPB bridge. As summarized here, Seybold et al. find that all 3 proteins stabilize each other’s presence at the bridge and that, while Cdc31 crosslinks rod-shaped Sfi1 molecules to form the bulk of structure, Kar1 keeps the bridge anchored to the nuclear envelope, in which the SPBs are embedded.
Meanwhile, Moyer et al. describe how a protein called STIL promotes mammalian centriole duplication by activating the kinase Plk4. Authors Tyler Moyer and Andrew Holland explain their results in this month’s biobytes podcast, where you can also hear Stella Aronov and Motti Choder discuss their discovery (Aronov et al.) that yeast transport a pheromone-encoding mRNA to the tips of their mating projections in P body-like RNP granules. You can listen below or subscribe in iTunes.
That’s all for today, but there are plenty of other interesting papers for you to discover at our table of contents page here.
Cover image of the extended SPB bridge structure formed upon Kar1 overexpression © 2015 Seybold et al.