The calpain–calpastatin system and protein degradation in fusing myoblasts

AbstractCalpain (Ca2+-activated cysteine protease) induced proteolysis has been suggested to play a role in myoblast fusion. We previously found that calpastatin (the endogenous inhibitor of calpain) diminishes markedly in myoblasts during myoblast differentiation just prior to the start of fusion, allowing Ca2+-induced calpain activation at that stage. Here, we show that a limited degradation of some proteins occurs within the myoblasts undergoing fusion, but not in proliferating myoblasts. The protein degradation is observed at the stage when calpastatin is low. Protein degradation within the myoblasts and myoblast fusion are inhibited by EGTA, by the cysteine protease inhibitors calpeptin and E-64d and by calpastatin. The degradation appears to be selective for certain myoblast proteins. Integrin β1 subunit, talin and β-tropomyosin are degraded in the fusing myoblasts, whereas α-actinin, β-tubulin and α-tropomyosin are not. A similar pattern of degradation is observed in lysates of proliferating myoblasts when Ca2+ and excess calpain are added, a degradation that is inhibited by calpastatin. The results support the notion that degradation of certain proteins is required for myoblast fusion and that calpain participates in the fusion-associated protein degradation. Participation of calpain is made possible by a change in calpain/calpastatin ratio, i.e., by a diminution in calpastatin level from a high level in the proliferating myoblasts to a low level in the differentiating myoblasts. Degradation of certain proteins, known to be responsible for the stability of the membrane–skeleton organization and for the interaction of the cell with the extracellular matrix, would allow destabilization of the membrane and the creation of membrane fusion-potent regions

A Delphi study to determine the European core curriculum for Master programmes in genetic counselling.

Genetic counsellors have been working in some European countries for at least 30 years. Although there are great disparities between the numbers, education, practice and acceptance of these professionals across Europe, it is evident that genetic counsellors and genetic nurses in Europe are working autonomously within teams to deliver patient care. The aim of this study was to use the Delphi research method to develop a core curriculum to guide the educational preparation of these professionals in Europe. The Delphi method enables the researcher to utilise the views and opinions of a group of recognised experts in the field of study; this study consisted of four phases. Phases 1 and 4 consisted of expert workshops, whereas data were collected in phases 2 and 3 (n=35) via online surveys. All participants in the study were considered experts in the field of genetic counselling. The topics considered essential for genetic counsellor training have been organised under the following headings: (1) counselling; (2) psychological issues; (3) medical genetics; (4) human genetics; (5) ethics, law and sociology; (6) professional practice; and (7) education and research. Each topic includes the knowledge, skills and attitudes required to enable genetic counsellors to develop competence. In addition, it was considered by the experts that clinical practice should comprise 50% of the educational programme. The core Master programme curriculum will enable current courses to be assessed and inform the design of future educational programmes for European genetic counsellors

Collaborative learning about e-health for mental health professionals and service users in a structured anonymous online short course: pilot study.

BACKGROUND: Professionals are interested in using e-health but implementation of new methods is slow. Barriers to implementation include the need for training and limited awareness or experience. Research may not always convince mental health professionals (MHPs). Adding the 'voice' of mental health service users (MHSUs) in collaborative learning may help. Involving MHSUs in face-face education can be difficult. We had previously been unable to engage MHPs in online discussion with MHSUs. Here we assessed the feasibility of short online courses involving MHSUs and MHPs. METHODS: We ran three e-health courses, comprising live interactive webcast, week's access to a discussion forum, and final live interactive webcast. We recruited MHPs via posters, newsletters, and telephone from a local NHS trust, and online via mailing lists and personal contacts from NHS trusts and higher education. We recruited MHSUs via a previous project and an independent user involvement service. Participants were presented with research evidence about e-health and asked to discuss topics using professional and lived experience. Feasibility was assessed through recruitment and attrition, participation, and researcher workloads. Outcomes of self-esteem and general self-efficacy (MHSUs), and Internet self-efficacy and confidence (MHPs) were piloted. RESULTS: Online recruiting was effective. We lost 15/41 from registration to follow-up but only 5/31 that participated in the course failed to complete follow-up. Nineteen MHPs and 12 MHSUs took part and engaged with each other in online discussion. Feedback was positive; three-quarters of MHPs indicated future plans to use the Internet for practice, and 80% of MHSUs felt the course should be continued. Running three courses for 31 participants took between 200 to 250 hours. Before and after outcome measures were completed by 26/31 that participated. MHP Internet self-efficacy and general Internet confidence, MHSU self-esteem and general self-efficacy, all seemed reliable and seemed to show some increase. CONCLUSIONS: Collaborative learning between MHSUs and MHPs in a structured online anonymous environment over a one-week course is feasible, may be more practical and less costly than face-face methods, and is worthy of further study

Diversity and uniformity in genetic responsibility: moral attitudes of patients, relatives and lay people in Germany and Israel

The professional and institutional responsibility for handling genetic knowledge is well discussed; less attention has been paid to how lay people and particularly people who are affected by genetic diseases perceive and frame such responsibilities. In this exploratory study we qualitatively examine the attitudes of lay people, patients and relatives of patients in Germany and Israel towards genetic testing. These attitudes are further examined in the national context of Germany and Israel, which represent opposite regulatory approaches and bioethical debates concerning genetic testing. Three major themes of responsibility emerged from the inter-group and cross-cultural comparison: self-responsibility, responsibility for kin, and responsibility of society towards its members. National contrast was apparent in the moral reasoning of lay respondents concerning, for example, the right not to know versus the duty to know (self-responsibility) and the moral conflict concerning informing kin versus the moral duty to inform (responsibility for kin). Attitudes of respondents affected by genetic diseases were, however, rather similar in both countries. We conclude by discussing how moral discourses of responsibility are embedded within cultural (national, religious) as well as phenomenological (being affected) narratives, and the role of public engagement in bioethical discourse

Molecular Determinants of Survival Motor Neuron (SMN) Protein Cleavage by the Calcium-Activated Protease, Calpain

Spinal muscular atrophy (SMA) is a leading genetic cause of childhood mortality, caused by reduced levels of survival motor neuron (SMN) protein. SMN functions as part of a large complex in the biogenesis of small nuclear ribonucleoproteins (snRNPs). It is not clear if defects in snRNP biogenesis cause SMA or if loss of some tissue-specific function causes disease. We recently demonstrated that the SMN complex localizes to the Z-discs of skeletal and cardiac muscle sarcomeres, and that SMN is a proteolytic target of calpain. Calpains are implicated in muscle and neurodegenerative disorders, although their relationship to SMA is unclear. Using mass spectrometry, we identified two adjacent calpain cleavage sites in SMN, S192 and F193. Deletion of small motifs in the region surrounding these sites inhibited cleavage. Patient-derived SMA mutations within SMN reduced calpain cleavage. SMN(D44V), reported to impair Gemin2 binding and amino-terminal SMN association, drastically inhibited cleavage, suggesting a role for these interactions in regulating calpain cleavage. Deletion of A188, a residue mutated in SMA type I (A188S), abrogated calpain cleavage, highlighting the importance of this region. Conversely, SMA mutations that interfere with self-oligomerization of SMN, Y272C and SMNΔ7, had no effect on cleavage. Removal of the recently-identified SMN degron (Δ268-294) resulted in increased calpain sensitivity, suggesting that the C-terminus of SMN is important in dictating availability of the cleavage site. Investigation into the spatial determinants of SMN cleavage revealed that endogenous calpains can cleave cytosolic, but not nuclear, SMN. Collectively, the results provide insight into a novel aspect of the post-translation regulation of SMN