Ubiquitin, a central component of selective cytoplasmic proteolysis, is linked to proteins residing at the locus of non-selective proteolysis, the vacuole

Ubiquitin, an evolutionary highly conserved protein, is known to be involved in selective proteolysis in the cytoplasm. Here we show that ubiquitin-protein conjugates are also found in the yeast vacuole. Mutants defective in the major vacuolar endopeptidases, proteinase yscA and yscB, lead to accumulation of ubiquitin-protein conjugates in this cellular organelle.

“I Keep Hearing Reports on the News That it's a Real Problem at the Moment”: Public Health Nurses’ Understandings of Sexting Practices Among Young People

Over the past decade, the potential harms regarding young people's use of technology have attracted mounting political, media and research attention worldwide. One practice engaged in by many young people is that of “sexting” and the sharing of partially, or complete nude images (“selfies”). Such images are not always retained within private spaces and are prone to be shared, with significant psychosocial consequences for young people involved. A significant risk is the hidden nature of some online interactions, with potential for grooming and child sexual exploitation. As key professionals working with young people, public health nurses have potential to educate and explore the risks with them. Yet to date, to our knowledge there has been no research in relation to public health nurses’ understandings of the practices involved or their potential harms. A qualitative study was undertaken drawing theoretically on the common‐sense model (CSM) to frame the analysis. Eighteen semi‐structured interviews were conducted with public health nurses in a region of England in 2016. Data were analysed through thematic analysis, and mapped to the five domains of CSM. Public health nurses’ understandings of young people's sexting practices were shaped largely by media reports, rather than scientific, disciplinary knowledge. Sexting did not resonate with many public health nurses’ own experiences of being a young person and was therefore difficult to understand. All were able to express an opinion about the causes and consequences of sexting and we present these as a “perceived hierarchy of risk”. All public health nurses acknowledged the importance of their role in dealing with harm reduction associated with sexting among young people, but they need education and support to do this effectively and confidently. Findings can be transferred carefully to many contexts and countries because sexting is a practice among young people that transcends geographical boundaries

A cAMP-binding ectoprotein in the yeast Saccharomyces cerevisiae

tides 10, 593-595

K63-linked ubiquitin chains as a specific signal for protein sorting into the multivesicular body pathway

A growing number of yeast and mammalian plasma membrane proteins are reported to be modified with K63-linked ubiquitin (Ub) chains. However, the relative importance of this modification versus monoubiquitylation in endocytosis, Golgi to endosome traffic, and sorting into the multivesicular body (MVB) pathway remains unclear. In this study, we show that K63-linked ubiquitylation of the Gap1 permease is essential for its entry into the MVB pathway. Carboxypeptidase S also requires modification with a K63-Ub chain for correct MVB sorting. In contrast, monoubiquitylation of a single target lysine of Gap1 is a sufficient signal for its internalization from the cell surface, and Golgi to endosome transport of the permease requires neither its ubiquitylation nor the Ub-binding GAT (Gga and Tom1) domain of Gga (Golgi localizing, gamma-ear containing, ARF binding) adapter proteins, the latter being crucial for subsequent MVB sorting of the permease. Our data reveal that K63-linked Ub chains act as a specific signal for MVB sorting, providing further insight into the Ub code of membrane protein trafficking

The domain architecture of large guanine nucleotide exchange factors for the small GTP-binding protein Arf

BACKGROUND: Small G proteins, which are essential regulators of multiple cellular functions, are activated by guanine nucleotide exchange factors (GEFs) that stimulate the exchange of the tightly bound GDP nucleotide by GTP. The catalytic domain responsible for nucleotide exchange is in general associated with non-catalytic domains that define the spatio-temporal conditions of activation. In the case of small G proteins of the Arf subfamily, which are major regulators of membrane trafficking, GEFs form a heterogeneous family whose only common characteristic is the well-characterized Sec7 catalytic domain. In contrast, the function of non-catalytic domains and how they regulate/cooperate with the catalytic domain is essentially unknown. RESULTS: Based on Sec7-containing sequences from fully-annotated eukaryotic genomes, including our annotation of these sequences from Paramecium, we have investigated the domain architecture of large ArfGEFs of the BIG and GBF subfamilies, which are involved in Golgi traffic. Multiple sequence alignments combined with the analysis of predicted secondary structures, non-structured regions and splicing patterns, identifies five novel non-catalytic structural domains which are common to both subfamilies, revealing that they share a conserved modular organization. We also report a novel ArfGEF subfamily with a domain organization so far unique to alveolates, which we name TBS (TBC-Sec7). CONCLUSION: Our analysis unifies the BIG and GBF subfamilies into a higher order subfamily, which, together with their being the only subfamilies common to all eukaryotes, suggests that they descend from a common ancestor from which species-specific ArfGEFs have subsequently evolved. Our identification of a conserved modular architecture provides a background for future functional investigation of non-catalytic domains

Identification of a Guanine Nucleotide Exchange Factor for Arf3, the Yeast Orthologue of Mammalian Arf6

Small G proteins of the Arf and Rab families are fundamental to the organisation and activity of intracellular membranes. One of the most well characterised of these G proteins is mammalian Arf6, a protein that participates in many cellular processes including endocytosis, actin remodelling and cell adhesion. Exchange of GDP for GTP on Arf6 is performed by a variety of guanine nucleotide exchange factors (GEFs), principally of the cytohesin (PSCD) and EFA6 (PSD) families. In this paper we describe the characterisation of a GEF for the yeast orthologue of Arf6, Arf3, which we have named Yel1 (yeast EFA6-like-1) using yeast genetics, fluorescence microscopy and in vitro nucleotide exchange assays. Yel1 appears structurally related to the EFA6 family of GEFs, having an N-terminal Sec7 domain and C-terminal PH and coiled-coil domains. We find that Yel1 is constitutively targeted to regions of polarised growth in yeast, where it co-localises with Arf3. Moreover the Sec7 domain of Yel1 is required for its membrane targeting and for that of Arf3. Finally we show that the isolated Yel1 Sec7 domain strongly stimulates nucleotide exchange activity specifically on Arf3 in vitro

Health Literacy of People with Substitutive Private Health Insurance in Germany and Their Assessment of the Health System Performance According to Health Literacy Levels: Results from a Survey

Health literacy (HL) is a competence to find, understand, appraise, and apply health information and is necessary to maneuver the health system successfully. People with low HL are, e.g., under the risk of poor quality and safety of care. Previous research has shown that low HL is more prevalent among, e.g., people with lower social status, lower educational level, and among the elderly. In Germany, people with substitutive private health insurance (PHI) account for 11% of the population and tend to have a higher level of education and social status, but in-detail assessments of their HL are missing so far. Therefore, this study aimed to investigate the HL of PHI insureds in Germany, and to analyze their assessment of the health system according to their HL level. In 2018, 20,000 PHI insureds were invited to participate in a survey, which contained the HLS-EU-Q16, and items covering patient characteristics and the World Health Organization health systems framework goals (e.g., access, quality, safety, responsiveness). Low HL was found for 46.2% of respondents and was more prevalent, e.g., among men and insureds with a low subjective social status. The health system performance was perceived poorer by respondents with low HL. Future initiatives to strengthen health systems should focus on promoting HL