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Different classes of RNA molecules are synthesized in the eukaryotic nucleus and are exported through nuclear pore complexes to the cytoplasm by mobile export receptors. Small RNAs follow relatively simple export routes, whereas large RNAs assemble into complex ribonucleoproteins and require specific adaptor proteins.
Maintaining the balance between ATP production and consumption is essential for cell survival. AMP-activated protein kinase (AMPK) is an energy sensor that, when energy levels are low, stimulates catabolism to produce ATP and inhibits biosynthesis and proliferation to conserve ATP.
Recent studies on melanosome formation have provided insights into novel aspects of endosomal sorting that are involved in cell physiology, organelle biogenesis and amyloid formation. Genetic disorders that affect the formation of melanosomes and other lysosome-related organelles are revealing the molecular machinery that controls specialized sorting events.
The chromosomal passenger complex (CPC) orchestrates mitosis and meiosis at several different levels to ensure the accurate distribution of the genetic material to the daughter cells. Its functions range from the regulation of kinetochore–microtubule attachments to sister chromatid cohesion and cytokinesis.
Reactive oxygen species (ROS) have been shown to be toxic but also function as signalling molecules. Recent studies have provided insights into the mechanisms that regulate ROS homeostasis and provide specificity in ROS signalling from prokaryotes to mammals.
The replication of telomeres poses unique problems, which the cell solves through specific mechanisms that coordinate the synthesis of the leading and lagging strands at telomeres. These mechanisms integrate the conventional replication machinery, telomere maintenance systems, DNA response pathways and chromosomal organization.
Cell monolayers have serious limitations for cell biological investigations and for cell-based assays in drug screening and toxicity studies. However, the establishment of three-dimensional cultures as a mainstream approach requires the development of reliable protocols, new cell lines and suitable imaging techniques.
