Podosomes

Ros et al. show that the ER-resident chaperone calnexin (Cnx) and its partner ERp57 are trafficked to cell surface invadosomes and induce ECM degradation, promoting tumour invasiveness.

Invadosomes degrade extracellular matrix and facilitate cell invasion but their molecular composition is not fully understood. Here, the authors combine laser capture and mass spectrometry to map the proteome of invadosomes, showing that they rely on internal translational activity to maintain their structure.

The actomyosin cytoskeleton plays an important role in polarised cell migration. Here the authors identify lymphocyte-specific protein (LSP)-1 as a regulator of actomyosin contractility in macrophages, by competing with supervillin for myosin IIA activators acting specifically on the β-actin isoform.

Podosomes are adhesive cytoskeletal structures found in several cell types, but whether or how they are interconnected is not known. Here the authors demonstrate mesoscale connectivity of podosome clusters by imaging directional flow patterns of podosome components vinculin, talin and F-actin.