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Viral transmission from an infected cell to a target cell has been long appreciated to be more efficient than infection with a cell-free virus. New work using high-resolution, live-cell microscopy techniques provides important insights into the mechanisms underlying the efficiency of retrovirus transmission between cells.
Lymphocyte migration is activated in response to inflammation and largely depends on the modulation of actin dynamics, and remodelling of the cytoskeleton, following cytokine stimulation. A novel pathway modulating inflammatory-cell migration in vivo that involves the unlikeliest of partners, the inflammatory caspase-11 and Aip1 (an activator of cofilin-mediated actin depolymerization), has been identified.
Mitogen-activated protein kinase (MAPK) cascades process myriads of stimuli, generating receptor-specific cellular outcomes. New work exploits emergent mathematics of network inference to reveal distinct feedback designs of the RAF–MEK–ERK cascade induced by two different growth factors. The study shows that response specificity can arise from differential signal-induced wiring of overlapping protein networks.
Although the molecular machinery controlling aging has been well studied in lower organisms, it is unclear whether these mechanisms are conserved in mammals. A recent study supports a role for an evolutionarily conserved transcriptional pathway in maintaining the unlimited lifespan of haematopoietic stem cells.
Despite being largely a post-mitotic tissue, adult skeletal muscle exhibits a remarkable capacity for regeneration. A new study has shown that cells derived from mural cells (pericytes) from blood vessels in postnatal human skeletal muscle contribute to robust skeletal muscle regeneration after intra-arterial delivery into a dystrophic mouse model.