Assessing Markers of Reproducibility and Transparency in Smoking Behaviour Change Intervention Evaluations.

INTRODUCTION: Activities promoting research reproducibility and transparency are crucial for generating trustworthy evidence. Evaluation of smoking interventions is one area where vested interests may motivate reduced reproducibility and transparency. AIMS: Assess markers of transparency and reproducibility in smoking behaviour change intervention evaluation reports. METHODS: One hundred evaluation reports of smoking behaviour change intervention randomised controlled trials published in 2018-2019 were identified. Reproducibility markers of pre-registration; protocol sharing; data, material, and analysis script sharing; replication of a previous study; and open access publication were coded in identified reports. Transparency markers of funding and conflict of interest declarations were also coded. Coding was performed by two researchers, with inter-rater reliability calculated using Krippendorff's alpha. RESULTS: Seventy-one percent of reports were open access, and 73% were pre-registered. However, there are only 13% provided accessible materials, 7% accessible data, and 1% accessible analysis scripts. No reports were replication studies. Ninety-four percent of reports provided a funding source statement, and eighty-eight percent of reports provided a conflict of interest statement. CONCLUSIONS: Open data, materials, analysis, and replications are rare in smoking behaviour change interventions, whereas funding source and conflict of interest declarations are common. Future smoking research should be more reproducible to enable knowledge accumulation. This study was pre-registered: https://osf.io/yqj5p.

Hydrophobic handoff for direct delivery of peroxisome tail-anchored proteins.

Tail-anchored (TA) proteins are inserted into membranes post-translationally through a C-terminal transmembrane domain (TMD). The PEX19 protein binds peroxisome TA proteins in the cytoplasm and delivers them to the membrane through the PEX3 receptor protein. An amphipathic segment in PEX19 promotes docking on PEX3. However, how this leads to substrate insertion is unknown. Here we reconstitute peroxisome TA protein biogenesis into two sequential steps of substrate TMD engagement and membrane insertion. We identify a series of previously uncharacterized amphipathic segments in PEX19 and identify one whose hydrophobicity is required for membrane insertion, but not TMD chaperone activity or PEX3 binding. A membrane-proximal hydrophobic surface of PEX3 promotes an unconventional form of membrane intercalation, and is also required for TMD insertion. Together, these data support a mechanism in which hydrophobic moieties in the TMD chaperone and its membrane-associated receptor act in a concerted manner to prompt TMD release and membrane insertion.