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Residual stress in crystalline polymers can lead to material failure, but currently methods which can quantify residual stress in such materials are lacking. Here, by using fluorescent-type mechanochromophores, the authors develop a method to visualize and quantify low degrees of stress that arises from micro-mechanical forces during polymer crystallization.

The mechanisms maintaining peroxisomal membrane proteins remain to be fully elucidated. Here, the authors report that p97/VCP and FAF2/UBXD8 modulate the turnover of peroxisomal membrane proteins to prevent autophagic degradation of peroxisomes.

Native spider silk has desirable mechanical properties, but these are challenging to replicate in an artificial material. Here, the authors report the use of a microfluidic system to create continuous fibers based on recombinant spidroin.

The delivery of genetic material into plants is challenging due to the cell wall barrier. Here, the authors hybridize polymer-coated carbon nanotubes with functional peptides to deliver plasmid DNA cargo into intact plant mitochondria for transient expression and homologous recombination at high efficiency.

The Lys48-linked polyubiquitin-mediated proteasomal degradation in yeast depends on Cdc48 and its cofactors Ufd1 and Npl4. Here, the authors present crystal structures of Npl4 bound to Lys48-linked diubiquitin and the Npl4-binding motif of Ufd1, providing insights into the reaction mechanism of the Cdc48- Ufd1/Npl4 complex.

Hyperosmotic stress leads to a phase separation of the proteasome, triggered by interactions between RAD23B and ubiquitylated proteins, which bring together p97 and proteasome-associated proteins into nuclear proteolytic foci.

The 26S proteasome is assembled in several steps, however the extent to which this assembly occurs before or after transport into the nucleus remains unclear. Pack et al.show that full assembly can occur in the cytoplasm, and that a concatameric form of the fully assembled complex is a substrate for nuclear import.

Phosphorylation of insulin receptor substrate (IRS)-1/2 by insulin-like growth factor (IGF)-I receptor tyrosine kinase is essential for IGF signalling. Here, the authors show that monoubiquitination of IRS-2 by the ubiquitin ligase Nedd4 recruits IRS-2 to the cell membrane and increases IRS-2 phosphorylation and IGF signalling.

Ubiquitylation is a dynamic post-translational modification involved in the regulation of numerous cellular processes. Here the authors describe Ub-ProT: a method to measure the length of substrate-attached ubiquitin chains in biological samples, and demonstrate a critical role for chain length in directing substrates to specific cellular pathways.

Ubiquitin is a stable and soluble protein, but it is commonly found in inclusion bodies in neurodegenerative disorders and cancer. Here, Morimoto et al. report that increasing ubiquitin chain length leads to the formation of amyloid-like fibrils, which are degraded by an autophagy mechanism.

Non-human primate models of autism spectrum disorder (ASD) are few and not well characterised. Here, the authors describe synaptic function and gene expression changes in a marmoset model of ASD from birth to juvenile, highlighting its similarity to features observed in human ASD.

Akizuki et al. reveal an unexpected role for K63-linked ubiquitin chains and the E2 enzyme UBE2N in degrader-induced degradation of cIAP1 through the proteasome, demonstrating the diversity of the ubiquitin code used for targeted degradation.

Several protein quality control mechanisms are in place to trigger the rapid degradation of aberrant polypeptides and mRNAs. Here the authors describe a mechanism of ribosome-mediated quality control that involves the ubiquitination of ribosomal proteins by the E3 ubiquitin ligase Hel2/RQT1.

Atomic molecular dynamics simulations of the complexation of plasmid DNA in the presence of two types of cationic peptides clear the mechanism of plasmid DNA condensation for gene delivery systems.

Ubiquitin, known for its role in post-translational modification of other proteins, undergoes post-translational modification itself; after a decrease in mitochondrial membrane potential, the kinase enzyme PINK1 phosphorylates ubiquitin at Ser 65, and the phosphorylated ubiquitin then interacts with ubiquitin ligase (E3) enzyme parkin, which is also phosphorylated by PINK1, and this process is sufficient for full activation of parkin enzymatic activity.

Polypeptides containing periodic aromatic residues, 4-aminobenzoic acid (Abz), in their main chains were synthesized via papain-catalyzed chemoenzymatic polymerization of tripeptide ester monomers under moderate conditions in aqueous buffers. The secondary structures of the Abz-containing polypeptides were investigated by IR and wide-angle X-ray diffraction analysis. The WAXD profile of poly(GlyAbzGly) was similar to that of polyGly, whereas poly(AlaAbzAla) adopted a sheet-like structure similar to the β-sheet of polyAla.

A new peptide carrier that mimics the basic leucine zipper domain (bZIP) of DNA-binding proteins was designed, in which (LU)₄ is the leucine zipper motif and (KUA)₃ is the basic DNA-binding motif (U = α-aminoisobutyric acid). When mixed with pDNA, (KUA)₃-(LU)₄ peptide condensed DNA molecules to form nanoparticles. Furthermore, when complexes of the (KUA)₃-(LU)₄ peptide and pDNA were introduced into the leaves of Arabidopsis thaliana (A. thaliana), the reporter protein was expressed in plant cells. Thus, (KUA)₃-(LU)₄ is an efficient carrier of pDNA with high dissociation efficiency.

The atomic structure of amorphous materials is sensitive to processing history. Here, the simultaneous application of temperature and pressure to a Zr₅₀Cu₄₀Al₁₀ metallic glass causes nanocrystal formation and short- and medium-range ordering, and an increase in strength.

A degradable cross-linked polybutadiene was synthesized using a peptide-based cross-linker. As a degradable cross-linker, we synthesized poly(L-cysteine) (polyCys) by papain-catalyzed chemoenzymatic polymerization. The thiol-ene reaction between polybutadiene and polyCys was conducted in the presence of a radical initiator, resulting in the formation of an insoluble polybutadiene gel. The successful cross-linking and network formation was confirmed by Raman spectroscopy and viscoelastic analysis. Dynamic viscoelastic measurements of the cross-linked polybutadiene revealed the disappearance of slow relaxation mode. The polyCys-linked polybutadiene underwent degradation through acidic hydrolysis, allowing the recovery of soluble polybutadiene.

In the cross-sectional view of sealing gasket, the urethane sealing gasket is composed of urethane-based polymer as a matrix and heat-expandable hollow particles as independent air bubbles. The polyurethane matrix has a crosslinking structure with aliphatic diisocyanate aduct, PTMG, and bi- and trifunctional polyester pre-polymers. Not only by adjusting the mechanical properties with the blowing agent but also by being localized lubricants with talc on the surface, both excellent sealing and opening properties could be realized.