Snapshot: JBC’s ‘Recommended Reads’

Published August 01 2017

Every two weeks, the Journal of Biological Chemistry distributes a short roundup of papers and reviews that its editors think are worth your time. Here’s a glimpse of recent selections. Sign up to receive the JBC’s Recommended Reads at www.jbc.org/mission.

Yersinia effector protein-mediated phosphorylation of host gelsolin

causes calcium-independent activation leading to disruption of actin dynamics

Pavithra Singaravelu, Wei Lin Lee, Sheena Wee, Umesh Ghoshdastider, Ke Ding, Jayantha Gunaratne, Jonathan M. Grimes, Kunchithapadam Swaminathan and Robert C. Robinson

Pathogens of the genus Yersinia, including those that cause plague, inject virulence factors called Yops into host cells that disrupt regulation of the actin cytoskeleton. Swaminathan, Robinson and colleagues report that the kinase YopO phosphorylates and thereby constitutively activates the actin-severing host protein gelsolin. The resulting actin disassembly in host cells could be responsible for the parasite’s ability to thwart phagocytosis.
www.jbc.org/content/292/19/8092.

 

Mechanical forces regulate the reactivity of a thioester bond in a bacterial adhesin

Daniel J. Echelman, Alex Q. Lee and Julio M. Fernández

Adhesins are bacterial proteins that mediate adherence to surfaces, the first step in infection. Some adhesins from Gram-positive bacteria covalently attach to host-cell–surface ligands through a thioester bond. Fernandez and colleagues use single-molecule force spectroscopy to mechanically stretch adhesin domains and show that these force-dependent conformational changes influenced the reactivity of the bond, providing a possible mechanism for selectivity of adhesion.
www.jbc.org/content/292/21/8988.

 

Temperature-induced membrane remodeling in two closely related Bordetella species

reflects their adaptation to diverse environmental niches

Gabriela Seydlova, Jana Beranova, Ilona Bibova, Ana Dienstbier, Jakub Drzmisek, Jiri Masin, Radovan Fiser, Ivo Konopasek and Branislav Vecerek

The bacterial pathogen Bordetella pertussis is strictly adapted to human hosts, whereas B. bronchiseptica is also found in the environment. Vecerek and colleagues report that B. bronchiseptica adjusts its membrane fluidity, fatty-acid composition and production of virulence factors in response to temperature, whereas B. pertussis continued producing virulence factors at low temperatures without remodeling its membrane. These observations could be examples of trade-offs between optimal virulence and adaptive plasticity.
www.jbc.org/content/292/19/8048.

 

Modifiers of prion protein biogenesis and recycling

identified by a highly parallel endocytosis kinetics assay

Boris A. Ballmer, Rita Moos, Prisca Liberali, Lucas Pelkmans, Simone Hornemann, and Adriano Aguzzi

The prion protein PrPC is a cell-surface protein that, when misfolded into its isoform PrPSc, causes prion diseases. Aguzzi and colleagues developed a high-throughput FRET-based assay to visually monitor PrPC internalization in real time. Using this method in combination with RNA knockdowns, the authors identified proteins involved in prion-protein trafficking. The authors propose that by allowing detailed analysis of prion biogenesis and trafficking, this method could be used to screen potential drugs for treating prion diseases.
www.jbc.org/content/292/20/8356.

 

The rare sugar N-acetylated viosamine is a major component of Mimivirus fibers

Francesco Piacente, Cristina De Castro, Sandra Jeudy, Matteo Gaglianone, Maria Elena Laugieri, Anna Notaro, Annalisa Salis, Gianluca Damonte, Chantal Abergel and Michela G. Tonetti

The capsid of the giant virus Mimivirus is surrounded by long fibers containing viosamine, a rare monosaccharide found in only a few bacteria. Tonetti and colleagues describe viosamine N-acetylation by a virus-encoded glycosyltransferase, hinting at possible relationships between these biosynthetic pathways in viruses and bacteria.
www.jbc.org/content/292/18/7385.

 

Nanomolar nitric oxide concentrations

quickly and reversibly modulate astrocytic energy metabolism

Alejandro San Martín, Robinson Arce-Molina, Alex Galaz, Gustavo Pérez-Guerra and L. Felipe Barros

Astrocytes are abundant brain cells proposed to play important roles in fueling neurons, and high concentrations of nitric oxide (NO) have been shown to influence astrocyte energy metabolism. Barros and colleagues now report that physiological concentrations of NO cause cultured astrocytes to reversibly upregulate the rate of glycolysis and accumulate lactate by blocking mitochondrial respiration, suggesting that NO signaling helps regulate energy fluxes in the brain.
www.jbc.org/content/292/22/9432.

 

Distinct modulatory role of RNA

in the aggregation of the tumor suppressor protein p53 core domain

Petar Stefanov Kovachev, Debapriya Banerjee, Luciana Pereira Rangel, Jonny Eriksson, Murilo M. Pedrote, Mafalda Maria D. C. Martins-Dinis, Katarina Edwards, Yraima Cordeiro, Jerson L. Silva and Suparna Sanyal

The tumor suppressor protein p53 is a transcription factor associated with various cancers when inactivated by mutation, protein–protein interaction or aggregation. Sanyal and collegues find that p53 aggregation can be influenced by interaction with RNA. Depending on the ratio of RNA to p53, RNA either induced or suppressed large amorphous aggregates or amyloid oligomers. These findings suggest that RNA structures may be involved in p53 regulation.
www.jbc.org/content/292/22/9345.