Cell Biology and Biophysics

It is in the cell where we will first understand the basic processes of life at the molecular level in a physiological context. The cell provides the natural coordinate system in space and time onto which we have to map and integrate genomic, transcriptomic, proteomic, structural and biophysical information about the molecules that make up living systems. In short, cell biology has become an integrative hub of much of modern biological research.

This is a time of tremendous opportunity for cell biology, but realising it also represents a formidable challenge and requires new concepts and approaches. Individual cellular processes ─ such as signalling, membrane trafficking, cytoskeletal dynamics and cell migration, gene expression or cell division ─ can no longer be studied in isolation but need to be considered as integrated events. The default situation is that the molecular machinery that performs these functions is complex and combinatorial at the single protein, protein complex, and pathway level. This requires new ways of thinking about cellular functions that use network biology and employing quantitative theoretical methods to generate mechanistic and predictive models that rely on realistic physical principles at the cellular, subcellular and molecular scale. Therefore, cell biology needs to integrate traditionally separate disciplines to realise its potential.

Novel developments in microscopy, computer simulations and chemical biology-based probes are a particular strength of the Unit. We constantly explore new directions and integrate new approaches and disciplines to answer cell biological questions. New correlative light/electron and super-resolution imaging methods, as well as mechanistic biochemistry, allow us to directly interface between cell and structural biology to understand molecular mechanisms. Furthermore, advances in live and deep tissue imaging methods now allow us to carry out cell biology in developing organisms to understand how collective cell behaviour leads to organ formation, and how cells interact with their physiological microenvironment.

Mechanisms of cellular functions are often best understood when the organisation of the cell changes dramatically to carry out new functions. This is the case when cells divide, when they change their fate. Both opportunities are exploited in the Unit. As a cell prepares to divide, all the microtubules suddenly depolymerise to reassemble into the mitotic spindle. At the same time, the nucleus is disassembled, mitotic chromosomes are formed, the Golgi complex fragments and membrane traffic ceases. After segregation of the genome is achieved, cellular organisation is re-established. Thus every cell cycle provides the opportunity to study the principles of the biogenesis of cellular compartments. Similarly, the genetic programme is changed and a reorganisation of cellular architecture takes place, guided by rules that we begin to unravel when progenitor cells differentiate into new cell types or start to migrate. Understanding these rules and principles is our challenge in the years to come.