A seesaw model for intermolecular gating in the kinesin motor protein

Recent structural observations of kinesin-1, the founding member of the kinesin group of motor proteins, have led to substantial gains in our understanding of this molecular machine. Kinesin-1, similar to many kinesin family members, assembles to form homodimers that use alternating ATPase cycles of the catalytic motor domains, or “heads”, to proceed unidirectionally along its partner filament (the microtubule) via a hand-over-hand mechanism. Cryo-electron microscopy has now revealed 8-Å resolution, 3D reconstructions of kinesin-1•microtubule complexes for all three of this motor’s principal nucleotide-state intermediates (ADP-bound, no-nucleotide, and ATP analog), the first time filament co-complexes of any cytoskeletal motor have been visualized at this level of detail. These reconstructions comprehensively describe nucleotide-dependent changes in a monomeric head domain at the secondary structure level, and this information has been combined with atomic-resolution crystallography data to synthesize an atomic-level "seesaw" mechanism describing how microtubules activate kinesin’s ATP-sensing machinery. The new structural information revises or replaces key details of earlier models of kinesin’s ATPase cycle that were based principally on crystal structures of free kinesin, and demonstrates that high-resolution characterization of the kinesin–microtubule complex is essential for understanding the structural basis of the cycle. I discuss the broader implications of the seesaw mechanism within the cycle of a fully functional kinesin dimer and show how the seesaw can account for two types of "gating" that keep the ATPase cycles of the two heads out of sync during processive movement

Leadership Practices in Hospital Nursing: A Self of Manager Nurses

OBJECTIVE To assess the frequency of the leadership practices performed by the manager nurses of hospital institutions and their association with the variables of the socioprofessional profile. METHOD Cross-sectional, descriptive, correlational study conducted in four hospitals in a city of the state of São Paulo. A sociodemographic questionnaire and the instrument Leadership Practices Inventory were used. Data collection and analysis were based on an exemplary Leadership Practices Model. RESULTS Eighty-four manager nurses participated in the study. The mean values of the leadership practices used by the nurses were: enable others to act (50.6); encourage the heart (48.2); model the way (46.7); challenge the process (43.3); and inspire a shared vision (43.1). Data analysis also evidenced a correlation between the practice encourage the heart and the variables time of care and employment relationship. Conclusion The study evidenced the presence of manager nurses exercising moderate leadership, and promoting teamwork, an environment of trust, and a horizontal vision. However, moderate values also reveal managerial aspects to be improved by the leaders by means of organizational strategies and/or tools aimed at best leadership practices.OBJETIVO Avaliar a frequência das práticas de liderança executadas pelos enfermeiros gerentes de instituições hospitalares e sua associação às variáveis do perfil socioprofissional. MÉTODO Estudo transversal, descritivo e correlacional, realizado em quatro hospitaisde um município do interior paulista. Utilizou-se de questionário sociodemográfico e do instrumento Leadership Practices Inventory. A coleta e a análise de dados foram fundamentadas em um Modelo de Práticas para Liderança exemplar. RESULTADOS Participaram 84 enfermeiros gerentes. As médias das práticas de liderança utilizadas pelos enfermeiros foram: capacitar os outros a agir (50,6), encorajar o coração (48,2), traçar o caminho (46,7), desafiar o processo (43,3) e inspirar uma visão compartilhada (43,1). Na análise dos dados também se constatou correlação entre a prática encoraje o coração e as variáveis tempo de assistência e vínculo empregatício. CONCLUSÃO O estudo constatou a presença de enfermeiros gerentes exercendo liderança moderada, promovendo o trabalho em equipe, propiciando um clima de confiança e visão horizontalizada. No entanto, os valores moderados também revelam aspectos gerenciais a serem aprimorados pelos líderes, por meio de ferramentas e/ou estratégias organizacionais em busca de melhores práticas de liderança.OBJETIVO Evaluar la frecuencia de las prácticas de liderazgo llevadas a cabo por los enfermeros gestores de instituciones hospitalarias y su asociación con las variables del perfil socioprofesional. MÉTODO Estudio transversal, descriptivo y correlacional, realizado en cuatro hospitales de un municipio del interior del Estado de São Paulo. Se utilizó un cuestionario sociodemográfico y el instrumento Leadership Practices Inventory. La recolección y el análisis de datos se fundaron en un Modelo de Prácticas para Liderazgo ejemplar. RESULTADOS Participaron 85 enfermeros gestores. Los promedios de las prácticas de liderazgo utilizados por los enfermeros fueron: capacitar a los otros a actuar (50,6), animar el corazón (48,2), trazar el camino (46,7), desafiar el proceso (43,3) e inspirar una visión compartida (43,1). En el análisis de datos también se constató correlación entre la práctica "anime el corazón" y las variables tiempo de asistencia y vínculo de empleo. CONCLUSIÓN El estudio constató la presencia de enfermeros gestores ejerciendo liderazgo moderado, promoviendo el trabajo en equipo, proporcionando un clima de confianza y visión horizontal. Sin embargo, los valores moderados también desvelaron aspectos de gestión que los líderes deben perfeccionar mediante herramientas y/o estrategias organizativas en búsqueda de mejores prácticas de liderazgo