ASCB Newsletter Nov 2013 - page 34

Protein kinase C activation decreases peripheral actin network density and increases central
nonmuscle myosin II contractility in neuronal growth cones
Qing Yang, Xiao-Feng Zhang, D. Van Goor, A. P. Dunn, C. Hyland, N. Medeiros, and P. Forscher
PKC activation enhances myosin II contractility in the central growth cone domain while decreasing actin
density and increasing actin network flow rates in the peripheral domain. This dual mode of action has
mechanistic implications for interpreting reported effects of PKC on growth cone guidance and neuronal
Mol. Biol. Cell 24 (19), 3097–3114
Chromosome replication and segregation govern the biogenesis and inheritance of inorganic
polyphosphate granules
J. T. Henry and S. Crosson
The Caulobacter polyphosphate synthesis enzyme, Ppk1, dynamically localizes to sites of polyphosphate
granule production during the cell cycle by virtue of a C-terminal localization sequence. The processes of
chromosome replication and segregation ensure that mother and daughter cells inherit a single granule
upon cell division.
Mol. Biol. Cell 24 (20), 3177–3186
The Editorial Board of
Molecular Biology of the Cell
has highlighted the following articles from the
October 2013 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.
During striated muscle differentiation numerous proteins associate in a multistep process to form
almost crystalline myofibrils. Xin actin-binding repeat-containing protein 1 (Xin) is associated with early
differentiation–stage premyofibrils but is excluded from mature myofibrils. Interestingly, Xin reappears
upon muscle damage or remodeling. This image shows the localization of Xin (green) and a Z-disc
epitope of one of its binding partners, nebulin (red), in a spontaneously contracting mouse myotube in
culture. The two proteins colocalize in nonstriated fibrils. Mature myofibrils contain nebulin but not Xin.
Contraction of the myotube leads to mechanical damage associated with the appearance of small Xin-
containing longitudinal filamentous structures that span one or a few sarcomeres and seem to attach to
the nebulin-containing Z-discs. See Mol. Biol. Cell 24, 3215–3226. (Image: Stefan Eulitz, University of
Bonn, Germany)
1...,24,25,26,27,28,29,30,31,32,33 35,36,37,38,39,40
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