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.

Cell Motility and Cytokinesis: From Mysteries to Molecular Mechanisms in Five Decades.

This is the story of someone who has been fortunate to work in a field of research where essentially nothing was known at the outset but that blossomed with the discovery of profound insights about two basic biological processes: cell motility and cytokinesis. The field started with no molecules, just a few people, and primitive methods. Over time, technological advances in biophysics, biochemistry, and microscopy allowed the combined efforts of scientists in hundreds of laboratories to explain mysterious processes with molecular mechanisms that can be embodied in mathematical equations and simulated by computers. The success of this field is a tribute to the power of the reductionist strategy for understanding biology.

Cytoplasmic Intermediate Filaments in Cell Biology.

Intermediate filaments (IFs) are one of the three major elements of the cytoskeleton. Their stability, intrinsic mechanical properties, and cell type-specific expression patterns distinguish them from actin and microtubules. By providing mechanical support, IFs protect cells from external forces and participate in cell adhesion and tissue integrity. IFs form an extensive and elaborate network that connects the cell cortex to intracellular organelles. They act as a molecular scaffold that controls intracellular organization. However, IFs have been revealed as much more than just rigid structures. Their dynamics is regulated by multiple signaling cascades and appears to contribute to signaling events in response to cell stress and to dynamic cellular functions such as mitosis, apoptosis, and migration.

iPS Cells 10 Years Later.

In 2006, Takahashi and Yamanaka reported the breakthrough discovery of induction of pluripotent stem cells from fibroblasts by a combination of defined factors. Ten years later, Cell editor João Monteiro brings together Shinya Yamanaka and Hans Schöler, one the original reviewers of the landmark study, to revisit the history behind the paper and its long-lasting legacy.

Illuminating the Dark Proteome.

A large segment of the proteome consists of disordered regions, yet in most cases, little is known about their mechanisms and functions. What are the roles of protein disorder in cell biology, and how do intrinsically disordered proteins function? These are the questions Cell's Robert Kruger posed to Madan Babu, Julie Forman-Kay, and Richard Kriwacki. Annotated excerpts from this conversation are presented below, and the full conversation is available with the article online. PAPERCLIP.

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.

Cryo-EM in molecular and cellular biology.

This review summarizes the current state of methods and results achievable by cryo-electron microscopy (cryo-EM) imaging for molecular, cell, and structural biologists who wish to understand what is required and how it might help to address their research questions. It covers some of the main issues in sample preparation, microscopes and data collection, image processing, three-dimensional (3D) reconstruction, and validation and interpretation of the resulting EM density maps and atomic models.

Technological advances in super-resolution microscopy to study cellular processes.

Since its initial demonstration in 2000, far-field super-resolution light microscopy has undergone tremendous technological developments. In parallel, these developments have opened a new window into visualizing the inner life of cells at unprecedented levels of detail. Here, we review the technical details behind the most common implementations of super-resolution microscopy and highlight some of the recent, promising advances in this field.

Fluorescence nanoscopy in cell biology.

Fluorescence nanoscopy uniquely combines minimally invasive optical access to the internal nanoscale structure and dynamics of cells and tissues with molecular detection specificity. While the basic physical principles of 'super-resolution' imaging were discovered in the 1990s, with initial experimental demonstrations following in 2000, the broad application of super-resolution imaging to address cell-biological questions has only more recently emerged. Nanoscopy approaches have begun to facilitate discoveries in cell biology and to add new knowledge. One current direction for method improvement is the ambition to quantitatively account for each molecule under investigation and assess true molecular colocalization patterns via multi-colour analyses. In pursuing this goal, the labelling of individual molecules to enable their visualization has emerged as a central challenge. Extending nanoscale imaging into (sliced) tissue and whole-animal contexts is a further goal. In this Review we describe the successes to date and discuss current obstacles and possibilities for further development.

Siri of the cell: what biology could learn from the iPhone.

Modern genomics is very efficient at mapping genes and gene networks, but how to transform these maps into predictive models of the cell remains unclear. Recent progress in computer science, embodied by intelligent agents such as Siri, inspires an approach for moving from networks to multiscale models able to predict a range of cellular phenotypes and answer biological questions.

Cell line: 2004-2014.

2014 marks Cell's 40th anniversary, and over the year we have looked back at how discoveries of the last four decades have molded our understanding of biology. The final decade of the Cell Line features a selection of the exceptional scientific work-both landmark papers and essential reviews. Select entries can be read as an "Annotated Classic," which includes the original paper and accompanying reflections of a leading scientist, considering the work from our current vantage point. Our last installment includes a harbinger of the interplay between microbiota and mammalian hosts in 2004, revolutionary papers in 2006 and 2007 unlocking cellular reprogramming, the discovery of beige adipocytes in 2012, and the first example of CRISPR-based genome editing in a nonhuman primate in 2014. In addition to landmark publications, there were innovative developments at the journal in this decade, with the complete redesign of the print journal and the creation of Leading Edge in late 2005 and the restructuring of the online display of the article in 2010. Keeping pace with the changing nature of biological research, over the decade Cell added new article types, introduced guidelines for the organization of supplementary material, and expanded the journal's web-based content to bring editors' and authors' excitement and perspective on individual papers to the readership. An interactive version of the timeline, with links to the papers, full author lists, and Annotated Classics, is available at http://dx.doi.org/10.1016/j.cell.2014.11.004.

Faculty searches get a facelift.

Hiring committees address the glut of highly qualified applicants for faculty positions by experimenting with new evaluation methods and adapting their expectations for today's increasingly competitive academic environment.

The ribosome emerges from a black box.

Although the basic facts about the ribosome were already known 40 years ago, elucidating its atomic structure and molecular mechanisms required sheer persistence and the innovative use of new technology and methods. These advances have transformed our understanding of translation in the cell.

A tale of chromatin and transcription in 100 structures.

To celebrate a century of X-ray crystallography, I describe how 100 crystal structures influenced chromatin and transcription research.

Microtubules: 50 years on from the discovery of tubulin.

Next year will be the 50th anniversary of the discovery of tubulin. To celebrate this discovery, six leaders in the field of microtubule research reflect on key findings and technological breakthroughs over the past five decades, discuss implications for therapeutic applications and provide their thoughts on what questions need to be addressed in the near future.

Capillary forces generated by biomolecular condensates.

Liquid-liquid phase separation and related phase transitions have emerged as generic mechanisms in living cells for the formation of membraneless compartments or biomolecular condensates. The surface between two immiscible phases has an interfacial tension, generating capillary forces that can perform work on the surrounding environment. Here we present the physical principles of capillarity, including examples of how capillary forces structure multiphase condensates and remodel biological substrates. As with other mechanisms of intracellular force generation, for example, molecular motors, capillary forces can influence biological processes. Identifying the biomolecular determinants of condensate capillarity represents an exciting frontier, bridging soft matter physics and cell biology.

Basic statistics in cell biology.

The physicist Ernest Rutherford said, "If your experiment needs statistics, you ought to have done a better experiment." Although this aphorism remains true for much of today's research in cell biology, a basic understanding of statistics can be useful to cell biologists to help in monitoring the conduct of their experiments, in interpreting the results, in presenting them in publications, and when critically evaluating research by others. However, training in statistics is often focused on the sophisticated needs of clinical researchers, psychologists, and epidemiologists, whose conclusions depend wholly on statistics, rather than the practical needs of cell biologists, whose experiments often provide evidence that is not statistical in nature. This review describes some of the basic statistical principles that may be of use to experimental biologists, but it does not cover the sophisticated statistics needed for papers that contain evidence of no other kind.

Education, Experience, and Action: An Interview with Dr. Trevor K. Archer.

We asked Dr. Archer about his experiences in academia, struggles he has faced, and thoughts on addressing racial bias. We hope that this series sparks a larger discussion of issues faced by underrepresented scientists and ways the scientific community can foster diversity and better support underrepresented scientists. The opinions expressed here are those of Dr. Archer and not the NIH/NIEHS or the US government.