HIGHLIGHTS from MBoC

The actomyosin contractile ring, composed largely of nonmuscle myosin II and actin, drives cleavage furrow ingression and facilitates the separation of daughter cells during cytokinesis. In this structured illumination microscopy image, the cleavage furrow of a dividing HeLa cell is shown to be made up of large, parallel nonmuscle myosin II stacks, whose rod domains (green) are flanked by nonmuscle myosin II motor domains (purple). Fenix et al. (Mol. Biol. Cell 27, 1465–1478) elucidate mechanisms of nonmuscle myosin II stack formation in both interphase and mitotic mammalian cells. This HeLa cell was transiently transfected with an N-terminal myosin II-GFP construct that labels the motors (purple), and stained via indirect immunofluorescence for the C-terminal rod domain (green). (Image: Aidan Fenix and Dylan Burnette, Vanderbilt University).

The actomyosin contractile ring, composed largely of nonmuscle myosin II and actin, drives cleavage furrow ingression and facilitates the separation of daughter cells during cytokinesis. In this structured illumination microscopy image, the cleavage furrow of a dividing HeLa cell is shown to be made up of large, parallel nonmuscle myosin II stacks, whose rod domains (green) are flanked by nonmuscle myosin II motor domains (purple). Fenix et al. (Mol. Biol. Cell 27, 1465–1478) elucidate mechanisms of nonmuscle myosin II stack formation in both interphase and mitotic mammalian cells. This HeLa cell was transiently transfected with an N-terminal myosin II-GFP construct that labels the motors (purple), and stained via indirect immunofluorescence for the C-terminal rod domain (green). (Image: Aidan Fenix and Dylan Burnette, Vanderbilt University).

The Editorial Board of Molecular Biology of the Cell has highlighted the following articles from the May 2016 issues. From among the many fine articles in the journal, the Board selects for these Highlights articles that are of broad interest and significantly advance knowledge or provide new concepts or approaches that extend our understanding.

Subcellular optogenetic activation of Cdc42 controls local and distal signaling to drive immune cell migration
Patrick R. O’Neill, Vani Kalyanaraman, and N. Gautam
Cdc42 is believed to play an important role in controlling the polarity of migrating cells, but it has not been possible to directly determine the effects of localized Cdc42 activity. Optogenetic activation of Cdc42 at one side of the cell was used to identify local and distal signaling responses that contribute to directed cell migration.
Mol. Biol. Cell 27 (9), 1442–1450

Expansion and concatenation of nonmuscle myosin IIA filaments drive cellular contractile system formation during interphase and mitosis
Aidan M. Fenix, Nilay Taneja, Carmen A. Buttler, John Lewis, Schuyler B. Van Engelenburg, Ryoma Ohi, and Dylan T. Burnette
Stacks of nonmuscle myosin IIA filaments form by the expansion of single filaments and concatenation of multiple filaments. Expansion is the dominant mechanism and is characterized by distinct structural steps. It is dependent on both motor activity and actin filament concentration. Expansion and catenation occur in both crawling and dividing cells.
Mol. Biol. Cell 27 (9), 1465–1478

Rga6 is a fission yeast Rho GAP involved in Cdc42 regulation of polarized growth
M. T. Revilla-Guarinos, Rebeca Martín-García, M. Antonia Villar-Tajadura, Miguel Estravís, Pedro M. Coll, and Pilar Pérez
Spatial regulation of Cdc42 activity is essential to maintain polarized growth. Fission yeast Rga6 is a new Cdc42 GTPase-activating protein (GAP) that collaborates with Rga4, the only known Cdc42 GAP, in the spatial restriction of active Cdc42 at the cell tip. Both GAPs localize preferentially at the nongrowing areas of the membrane in different clusters.
Mol. Biol. Cell 27 (9), 1524–1535

About the Author: