Bridging structural and cell biology with cryo-electron microscopy.

Most life scientists would agree that understanding how cellular processes work requires structural knowledge about the macromolecules involved. For example, deciphering the double-helical nature of DNA revealed essential aspects of how genetic information is stored, copied and repaired. Yet, being reductionist in nature, structural biology requires the purification of large amounts of macromolecules, often trimmed off larger functional units. The advent of cryogenic electron microscopy (cryo-EM) greatly facilitated the study of large, functional complexes and generally of samples that are hard to express, purify and/or crystallize. Nevertheless, cryo-EM still requires purification and thus visualization outside of the natural context in which macromolecules operate and coexist. Conversely, cell biologists have been imaging cells using a number of fast-evolving techniques that keep expanding their spatial and temporal reach, but always far from the resolution at which chemistry can be understood. Thus, structural and cell biology provide complementary, yet unconnected visions of the inner workings of cells. Here we discuss how the interplay between cryo-EM and cryo-electron tomography, as a connecting bridge to visualize macromolecules in situ, holds great promise to create comprehensive structural depictions of macromolecules as they interact in complex mixtures or, ultimately, inside the cell itself.

Moving structural biology forward together.

Continuing the celebration of Cell's 50th anniversary, this Focus Issue is an ode to the field of Structural Biology. We present Leading Edge articles highlighting specific approaches and insights that this field offers to answer fundamental and critical biological questions.

The beauty and challenges of studying cell biology in diverse organisms.

Cell Reports Editor Shawnna Buttery interviewed Holly Goodson, Wallace Marshall, and Thibaut Brunet at the annual ASCB/EMBO Cell Bio conference. Shawnna asked how non-traditional organisms help us better understand the fundamentals of cell biology. A transcript of the conversation appears below, and the full conversation is available with the article online.

Celebrating our origins with cell biology.

Cell's 50th anniversary celebrations begin with our special focus issue on cell biology. Foundational and critical to our understanding of life and mechanisms of disease, explore Leading Edge content covering exciting frontiers of this field.

Análise do perfil epidemiológico dos exames citopatológico do colo do útero em Altamira no período de 2014 a 2020: dados a partir do SISCAN / Analysis of the epidemiological profile of cervical cytopathological exams in Altamira in the period from 2014 to 2020: data from SISCAN / Análisis del perfil epidemiológico de los exámenes citopatológicos de cérvix en Altamira en el periodo de 2014 a 2020: datos del SISCAN

OBJETIVO: Este trabalho aborda sobre características referente aos exames citopatológicos do colo do útero em Altamira, coletado no Sistema de Informação do Câncer, dentro do período de 2014 a 2020. Observou-se também a qualidade da interpretação dos principais resultados encontrados, sobre a técnica de coleta e qualidade de exames. O objetivo é analisar o perfil epidemiológico dos exames citopatológicos do colo do útero do município. MÉTODO: A metodologia realizada foi estudo quantitativo, de corte transversal, epidemiológico, descritiva e analítico. RESULTADOS: Verificou- se um crescimento anual na taxa de cobertura do exame do preventivo no período de 2014 a 2019, que está ligado à implementação do Plano de Desenvolvimento Regional Sustentável do Xingu, e que esse crescimento mostra uma diferença estatística significativa entre a taxa de cobertura de Altamira, Pará, Brasil. Observou-se presença de falhas no preenchimento da ficha de notificação é referente ao campo da escolaridade das pacientes que não apresentam registro. Quanto a faixa etária mais frequente que realizam o exame do preventivo está entre 25 a 34 anos e as lesões intraepiteliais do colo uterino mais frequentes são: a de baixo grau que corresponde à população jovem (<34 anos) e de alto grau entre 25 a 44 anos.

OBJECTIVE: This paper deals with characteristics related to cytopathological examinations of the cervix in Altamira, collected in the Cancer Information System, within the period from 2014 to 2020. It was also observed the quality of interpretation of the main results found, on the technique collection and quality of exams. The objective is to analyze the epidemiological profile of cytopathological tests of the cervix in the city. METHOD: The methodology used was a quantitative, cross- sectional, epidemiological study, descriptive and analytical approach. RESULTS: As a result, there was an annual growth in the coverage rate of the preventive exam in the period from 2014 to 2019, which is linked to the implementation of the Xingu Sustainable Regional Development Plan, and that this growth shows a significant statistical difference between the coverage rate of Altamira, Pará, Brazil. It was observed the presence of failures in completing the notification form referring to the field of education of patients who do not have a record. As for the most frequent age group that undergoes the preventive examination, it is between 25 and 34 years old and the most frequent intraepithelial lesions of the uterine cervix are: low-grade, which corresponds to the young population (<34 years) and high-grade, between 25 and 34 years old. 44 years.

OBJETIVO: En este trabajo se abordan las características relacionadas con los exámenes citopatológicos de cérvix en Altamira, recogidos en el Sistema de Información del Cáncer, en el periodo comprendido entre 2014 y 2020. También se observó la calidad de interpretación de los principales resultados encontrados, sobre la técnica de recolección y calidad de los exámenes. El objetivo es analizar el perfil epidemiológico de los exámenes citopatológicos de cuello uterino en la ciudad. MÉTODO: La metodología utilizada fue un estudio cuantitativo, transversal, epidemiológico, de abordaje descriptivo y analítico. RESULTADOS: Como resultado, se observó un crecimiento anual de la tasa de cobertura del examen preventivo en el período de 2014 a 2019, que está vinculado a la implementación del Plan de Desarrollo Regional Sostenible Xingu, y que este crecimiento muestra una diferencia estadística significativa entre la tasa de cobertura de Altamira, Pará, Brasil. Se observó la presencia de fallas en el llenado del formulario de notificación referente al campo de la educación de los pacientes que no tienen un registro. En cuanto al grupo de edad más frecuente que se somete al examen preventivo, es entre 25 y 34 años y las lesiones intraepiteliales del cuello uterino más frecuentes son: de bajo grado, que corresponde a la población joven (<34 años) y de alto grado, entre 25 y 44 años.

Bioorthogonal Chemistry in Cellular Organelles.

While bioorthogonal reactions are routinely employed in living cells and organisms, their application within individual organelles remains limited. In this review, we highlight diverse examples of bioorthogonal reactions used to investigate the roles of biomolecules and biological processes as well as advanced imaging techniques within cellular organelles. These innovations hold great promise for therapeutic interventions in personalized medicine and precision therapies. We also address existing challenges related to the selectivity and trafficking of subcellular dynamics. Organelle-targeted bioorthogonal reactions have the potential to significantly advance our understanding of cellular organization and function, provide new pathways for basic research and clinical applications, and shape the direction of cell biology and medical research.

Underestimated Cervical Cancer among Women over 65 Years Old: Is It Time to Revise the Screening Target Age Group? / Câncer cervical subestimado entre mulheres com mais de 65 anos: É hora de rever a faixa etária alvo do rastreamento?

Abstract Objective To compare cytological and histological results from women > 64 years old who followed the Brazilian national cervical cancer screening guidelines with those who did not. Methods The present observational retrospective study analyzed 207 abnormal cervical smear results from women > 64 years old in a mid-sized city in Brazil over 14 years. All results were reported according to the Bethesda System. The women were divided into those who followed the screening guidelines and those who did not. Results Atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesion cytology results were found in 128 (62.2%) cases. Of these, 112 (87.5%) had repeated cytology with positive results. The other 79 (38.1%) with abnormal results should have been referred to colposcopy and biopsy. Out of 41 (51.9%) biopsied women, 23 (29.1%) had a confirmed diagnosis of neoplasia or precursor lesion. In contrast, among the 78 (37.7%) biopsied patients, 40 (51.3%) followed the guideline recommendations, with 9 (22.5%) positive biopsies. Of the 38 (48.7%) women who did not follow the guidelines, there were 24 (63.1%) positive results. Women who did not follow the guidelines demonstrated higher chances of cancer and precursor lesions (odds ratio [OR]: 5.904; 95% confidence interval [CI]: 2.188-15.932; p = 0.0002). Conclusion Women > 64 years old who did not follow the national screening protocol showed significant differences in the frequency of abnormal results and severity of diagnosis compared with those who followed the protocol.

Resumo Objetivo Comparar os resultados citológicos e histológicos de mulheres > 64 anos que seguiram as diretrizes nacionais brasileiras de rastreamento do câncer do colo do útero com aquelas que não as seguiram. Método O presente estudo observacional retrospectivo analisou 207 resultados anormais de esfregaço cervical de mulheres > 64 anos de idade em uma cidade de médio porte no Brasil durante 14 anos. Todos os resultados foram relatados de acordo com o Sistema Bethesda. As mulheres foram divididas entre as que seguiram as diretrizes de rastreamento e as que não o fizeram. Resultados Resultados citológicos com células escamosas atípicas de significado indeterminado e lesão intraepitelial escamosa de baixo grau foram encontrados em 128 (62,2%) casos. Destes, 112 (87,5%) repetiram a citologia com resultados positivos. Os outros 79 (38,1%) com resultados anormais deveriam ter sido encaminhados para colposcopia e biópsia. Das 41 (51,9%) mulheres biopsiadas, 23 (29,1%) tiveram diagnóstico confirmado de neoplasia ou lesão precursora. Em contrapartida, entre as 78 (37,7%) pacientes biopsiadas, 40 (51,3%) seguiram as recomendações da diretriz, com 9 (22,5%) biópsias positivas. Entre as 38 (48,7%) mulheres que não seguiram as orientações, houve 24 (63,1%) resultados positivos. As mulheres que não seguiram as diretrizes demonstraram maiores chances de câncer e lesões precursoras (odds ratio [OR]: 5,904; intervalo de confiança [IC] de 95%: 2,188-15,932; p = 0,0002). Conclusão Mulheres > 64 anos que não seguiram a diretriz nacional de rastreamento apresentaram diferenças significativas na frequência de resultados anormais e gravidade do diagnóstico em comparação com aquelas que seguiram a diretriz.

Robustness and complexity.

When a system robustly corrects component-level errors, the direct pressure on component performance declines. Components become less reliable, maintain more genetic variability, or drift neutrally, creating new forms of complexity. Examples include the hourglass pattern of biological development and the hourglass architecture for robustly complex systems in engineering.

Cell wall is a dead metaphor.

It was recently suggested to end the usage of the term cell wall in microbiology (including prokaryotes and fungi) because it represented an inappropriate and potentially misleading metaphor (Casadevall and Gow, 2022). The analysis of the arguments for such a move from the viewpoint of the plant physiologist indicates that the suggestion is based on misunderstandings, first, of the early history of cell biology and its terminology; second, of the development of modern concepts of cell wall function since the late 19th century; and third, of the nature of metaphors and their role in scientific communication. We conclude that misconceptions concerning cell walls may arise due to pedagogical shortcomings in introducing students to our technical terminology rather than from the fact that part of this terminology originated from metaphors.

Factores de riesgo asociados a la malignidad de nódulos tiroideos en mujeres adultas: Estudio observacional de centro único / Risk factors associated with malignancy of thyroid nodules in adult womens: A single-center observational study

Introducción: Aunque la mayoría de los nódulos tiroideos son benignos, asintomáticos y estables en la historia clínica de una paciente mujer; en los estudios ecográficos, citológicos e histopatológicos se ha podido obtener la caracterización subclínica de lesiones sugestivas de malignidad. El actual estudio tuvo por objetivo evaluar los factores de riesgo asociados a la malignidad de nódulos tiroideos en pacientes adultas. Metodología: Se realizó un estudio descriptivo, transversal, retrospectivo correlacional de enfoque mixto en el servicio de endocrinología del Hospital Teodoro Maldonado Carbo entre Enero y Junio del 2019. El universo estuvo compuesto por todos los casos con diagnóstico de nódulo tiroideo. Se utilizó el sistema de Bethesda para los reportes. Resultados: Fueron 132 casos de pacientes con nódulos tiroideos, edad entre 45 a 64 años (57,6%). En estado pre menopáusico (52%), con 1 gestación (12%), glucosa >100 mg/dL (34%), IMC entre 25.0 y 29.9 kg/m2 (49%) y con antecedente patológico familiar de cáncer de tiroides (35%). 30 casos con valores de TSH >4.00 uUI/mL (23%). El sistema de Bethesda, 22 casos (17%) categoria IV, 17 casos (13%) categoria V y 11 casos (8%) categoría VI. Conclusiones: La lesión citológica tiroidea más frecuente que se encontró fue la neoplasia benigna. No obstante, la lesión maligna junto con la lesión folicular indeterminada presentaron una prevalencia del 8%. Se encontró una asociación significativa entre los nódulos de citología maligna con los niveles de TSH elevados y con el antecedente patológico familiar de cáncer de tiroides.

Introduction: Although most thyroid nodules are benign, asymptomatic, and stable in the clinical history of a female patient, in ultrasound, cytological, and histopathological studies, it has been possible to obtain the subclinical characterization of lesions suggestive of malignancy. The current study aimed to evaluate the risk factors associated with the malignancy of thyroid nodules in adult patients. Methodology: A descriptive, cross-sectional, retrospective, correlational study with a mixed approach was carried out in the endocrinology service of the Teodoro Maldonado Carbo Hospital between January and June 2019. The study population consisted of all patients diagnosed with thyroid nodules. The Bethesda system was used for reporting. Results: There were 132 patients with thyroid nodules aged between 45 and 64 (57.6%). In a premenopausal state (52%), there was one pregnancy (12%), glucose >100 mg/dL (34%), BMI between 25.0 and 29.9 kg/m2 (49%) and a family history of thyroid cancer (35%). Thirty patients had TSH values >4.00 µUI/mL (23%). In the Bethesda system, 22 cases (17%) were Category IV, 17 cases (13%) were Category V, and 11 cases (8%) were Category VI. Conclusions: The most frequent thyroid cytological lesion found was a benign neoplasm. However, malignant lesions and indeterminate follicular lesions presented a prevalence of 8%. A significant association was found between malignant cytology nodules with elevated TSH levels and a family history of thyroid cancer.

Craig Montell.

Interview with Craig Montell, whose work focuses on identifying receptors, channels and sensory neurons important in vision, taste, and temperature sensation.

Development of ultrafast camera-based single fluorescent-molecule imaging for cell biology.

The spatial resolution of fluorescence microscopy has recently been greatly enhanced. However, improvements in temporal resolution have been limited, despite their importance for examining living cells. Here, we developed an ultrafast camera system that enables the highest time resolutions in single fluorescent-molecule imaging to date, which were photon-limited by fluorophore photophysics: 33 and 100 µs with single-molecule localization precisions of 34 and 20 nm, respectively, for Cy3, the optimal fluorophore we identified. Using theoretical frameworks developed for the analysis of single-molecule trajectories in the plasma membrane (PM), this camera successfully detected fast hop diffusion of membrane molecules in the PM, previously detectable only in the apical PM using less preferable 40-nm gold probes, thus helping to elucidate the principles governing the PM organization and molecular dynamics. Furthermore, as described in the companion paper, this camera allows simultaneous data acquisitions for PALM/dSTORM at as fast as 1 kHz, with 29/19 nm localization precisions in the 640 × 640 pixel view-field.

Ultrafast single-molecule imaging reveals focal adhesion nano-architecture and molecular dynamics.

Using our newly developed ultrafast camera described in the companion paper, we reduced the data acquisition periods required for photoactivation/photoconversion localization microscopy (PALM, using mEos3.2) and direct stochastic reconstruction microscopy (dSTORM, using HMSiR) by a factor of ≈30 compared with standard methods, for much greater view-fields, with localization precisions of 29 and 19 nm, respectively, thus opening up previously inaccessible spatiotemporal scales to cell biology research. Simultaneous two-color PALM-dSTORM and PALM-ultrafast (10 kHz) single fluorescent-molecule imaging-tracking has been realized. They revealed the dynamic nanoorganization of the focal adhesion (FA), leading to the compartmentalized archipelago FA model, consisting of FA-protein islands with broad diversities in size (13-100 nm; mean island diameter ≈30 nm), protein copy numbers, compositions, and stoichiometries, which dot the partitioned fluid membrane (74-nm compartments in the FA vs. 109-nm compartments outside the FA). Integrins are recruited to these islands by hop diffusion. The FA-protein islands form loose ≈320 nm clusters and function as units for recruiting FA proteins.

FREEDA: An automated computational pipeline guides experimental testing of protein innovation.

Cell biologists typically focus on conserved regions of a protein, overlooking innovations that can shape its function over evolutionary time. Computational analyses can reveal potential innovations by detecting statistical signatures of positive selection that lead to rapid accumulation of beneficial mutations. However, these approaches are not easily accessible to non-specialists, limiting their use in cell biology. Here, we present an automated computational pipeline FREEDA that provides a simple graphical user interface requiring only a gene name; integrates widely used molecular evolution tools to detect positive selection in rodents, primates, carnivores, birds, and flies; and maps results onto protein structures predicted by AlphaFold. Applying FREEDA to >100 centromere proteins, we find statistical evidence of positive selection within loops and turns of ancient domains, suggesting innovation of essential functions. As a proof-of-principle experiment, we show innovation in centromere binding of mouse CENP-O. Overall, we provide an accessible computational tool to guide cell biology research and apply it to experimentally demonstrate functional innovation.

Histochemistry and Cell Biology-a glance into the past and a look ahead.

At the occasion of the 65th anniversary of Histochemistry and Cell Biology, we browse through its first ten years of publication and highlight a selection of papers from the early days of enzyme, protein, and carbohydrate histochemistry. In addition, we narrate recent progress to identify, quantify, and precisely determine the tissue localization of proteins and lipids, and small molecules by the combination of spectroscopic techniques and histology.