Molecular Biology

Protein secretion routes in fungi are mostly determined by the length of the hydrophobic helix in the signal peptide

1. Tristan Sones-Dykes
2. Edward Wallace

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The spike tip protein of bacteriophage T4

1. Yves Mattenberger
2. Ekaterina S Knyazhanskaya
3. Mikhail M Shneider
4. Sergey A Buth
5. Sergey Nazarov
6. William P Robins
7. Petr G Leiman
8. Dominique Belin

• Curated by eLife

  eLife Assessment

  This important study by Mattenburger et al. employs structural biology, biochemistry, and genetics to advance understanding of how bacteriophage contractile injection systems mediate host recognition and DNA delivery, yielding a remarkable 1.15 A crystal structure of the T4 spike tip complex (gp5-gp5.4). The compelling evidence presented demonstrates that the spike tip protein gp5.4 is essential for phage fitness and successful infection of Escherichia coli strains bearing truncated lipopolysaccharide; however, direct proof regarding interaction with the cell wall or its components is lacking. The study further provides biochemical evidence that the analogous spike tip protein from phage P2 (GpV) is translocated into the host periplasm during infection, together establishing the spike tip as a critical and active component of the phage infection machinery.

Reviewed by eLife

Structural basis for the folding of PINK1 by the HSP90–CDC37 chaperone complex

1. Kei Okatsu
2. Hayato Yamamoto
3. Akinori Okamoto
4. Shinya H Goto
5. Yumiko Nishimoto
6. Yukihiko Sugita
7. Takeshi Noda
8. Shuya Fukai

• Curated by eLife

  eLife Assessment

  This study presents a high-quality cryo-EM structure of the human kinase PINK1 in complex with the HSP90-CDC37 chaperone complex, capturing a partially folded intermediate in which the C-lobe and C-terminal extension are structured while the N-lobe remains unfolded and engaged by the HSP90 clamp. The structural data are broadly consistent with a recently published structure of the same complex, providing useful insight into early steps of PINK1 maturation and highlighting residues linked to familial Parkinson's disease. However, the mechanistic conclusions remain incomplete because the manuscript does not experimentally validate key hypotheses raised by the structure, including the functional roles of the C-lobe interface, the HPNI motif, the C-terminal extension, or the proposed competition between HSP90 and TOM20.

Reviewed by eLife

FRG1 Regulates Nonsense-Mediated mRNA Decay by Modulating UPF1 Levels

1. Ananya Palo
2. Talina Mohapatra
3. Anamika Singh
4. Shithij Thalakkat
5. Suryasikha Mohanty
6. Rajeeb Kumar Swain
7. Manjusha Dixit

• Curated by eLife

  eLife Assessment

  This useful study by Palo et al proposes that FRG1 functions as a negative regulator of Nonsense-Mediated mRNA decay (NMD) by associating with the exon junction complex (EJC) and destabilizing UPF1 independently of DUX4. The authors present solid evidence to dissect the relationship between FRG1 and DUX4 in NMD. However, the evidence to support the claim that FRG1 is a component of the EJC or the NMD machinery is incomplete.

Reviewed by eLife

Specialization of ubiquitin ligases to distinct nucleic acid sensors

1. Ibrahim Syed
2. Sheng Chen
3. David J. Peeler
4. Paul F. McKay
5. Marco A. Briones-Orta
6. Jennifer A. Bohn
7. Robin J. Shattock
8. Daniel Gonçalves-Carneiro

Reviewed by Review Commons