Volume 25 Issue 12, December 2018

Recent advances in the ability to detect mRNA base modifications have led to a renewed appreciation for the diversity of the epitranscriptome and its ability to influence gene expression. Now, a study in Cell adds acetylated cytidine (ac⁴C) to the list, identifying it as a widespread mark in cellular mRNAs that influences both mRNA stability and translation.

Diederichs and colleagues review RNA motifs, focusing on four recent studies identifying nuclear-retention motifs, and discuss the limited specificity of short RNA motifs and the resulting challenge for effective functional prediction.

This Review discusses mechanistic insights into 5´–3´ RNA decay, such as translation–decay coupling, coordination between complexes that process 5´ & 3´ RNA termini, conformational control of enzymatic activity, phase separation, & RNA modifications.

This structure of human PTH1R, a key target for the treatment of osteoporosis, reveals the agonist binding mode and molecular details within conserved structural motifs critical for class B GPCR function.

A PxL motif is identified in substrates of yeast phosphatase Cdc14. PxL functions as a docking motif for substrates and contributes to the timing of dephosphorylation during mitotic exit.

Point centromeres of budding yeast direct binding of a CBF3 complex that recruits the centromere-specific Cse4 nucleosome to CEN loci. A cryo-EM structure of CBF3 bound to its cognate CDEIII element and a model of the CBF3–Cse4–CEN complex reveal interactions underlying kinetochore assembly.

Single-molecule magnetic tweezers analyses and supporting MD simulations provide evidence for protein-gate opening of type IA topoisomerases.

A combination of proteomics and structural analyses reveals the assembly mechanism of transcription factor TFIID in human cells and identifies the chaperonin CCT as a checkpoint in the process.

Rubinstein and colleagues report a structure of the obligate respiratory III₂IV₂ supercomplex from M. smegmatis, revealing two functionally relevant conformations of the cytochrome cc subunit and a SOD subunit that may detoxify reactive oxygen species.