The crystal structure of the Sgt1-Skp1 complex: the link between Hsp90 and both SCF E3 ubiquitin ligases and kinetochores

The essential cochaperone Sgt1 recruits Hsp90 chaperone activity to a range of cellular factors including SCF E3 ubiquitin ligases and the kinetochore in eukaryotes. In these pathways Sgt1 interacts with Skp1, a small protein that heterodimerizes with proteins containing the F-box motif. We have determined the crystal structure of the interacting domains of Saccharomyces cerevisiae Sgt1 and Skp1 at 2.8 Å resolution and validated the interface in the context of the full-length proteins in solution. The BTB/POZ domain of Skp1 associates with Sgt1 via the concave surface of its TPR domain using residues that are conserved in humans. Dimerization of yeast Sgt1 occurs via an insertion that is absent from monomeric human Sgt1. We identify point mutations that disrupt dimerization and Skp1 binding in vitro and find that the interaction with Skp1 is an essential function of Sgt1 in yeast. Our data provide a structural rationale for understanding the phenotypes of temperature-sensitive Sgt1 mutants and for linking Skp1-associated proteins to Hsp90-dependent pathways

Exame Papanicolaou: sentimentos relatados por profissionais de enfermagem ao se submeterem a esse exame Pap smear screening: sensations reported by nursing professionals when submitted to this test

Objetivou-se conhecer os sentimentos de auxiliares e técnicas de enfermagem ao se submeterem ao exame Papanicolaou. Trata-se de um estudo descritivo com abordagem qualitativa realizado nos meses de setembro a outubro de 2006, com 35 servidoras de uma instituição governamental referência em ginecologia na cidade de Fortaleza (CE). Os dados foram coletados através de entrevista semiestruturada, contendo uma questão norteadora gravada e analisada de acordo com referencial teórico metodológico da fenomenologia social. Os relatos foram agrupados em três temáticas: um exame que causa incômodo, medo e vergonha; um exame que gera ansiedade quanto aos resultados; e um exame que "me deixa calma e tranquila". Apesar de as entrevistadas pertencerem a uma instituição que cuida de mulheres na prevenção do câncer cérvico-uterino, elas não deixaram de emitir sentimentos negativos relacionados ao exame. Concluiu-se a importância de realizar projetos educativos, enfatizando a importância do empoderamento das usuárias a fim de minimizar essas questões.<br>This work sought to record the impressions of nursing assistants and technicians after submitting to Pap smear screening. This is a descriptive study using a qualitative approach conducted in September and October of 2006 with 35 employees of a public institution, which is a benchmark in gynecology in Fortaleza in the State of Ceará (Brazil). The data was collected through semi-structured interviews containing a recorded leading question and analyzed according to the methodological-theoretical reference of social phenomenology. The testimonials were separated in three groups: an exam that causes discomfort, fear and shame; an exam that causes anxiety about the results; and an exam that "makes me calm and relaxed". Despite the interviewees being part of an institution that cares for the prevention of cervical-uterine cancer in women, negative feelings about the Pap smear test were nonetheless reported. The conclusion reached is that it is important to stage educational campaigns emphasizing the importance of empowerment of patients in order to minimize these aspects