Linear ubiquitin chains break blood vessel branches

New work published in Molecular Cell by Fu et al. reveals that the protein kinase ALK1 is deregulated when the enzymes assembling and disassembling Met1-ubiquitination, LUBAC and OTULIN, are inhibited or missing. This latest non-degradative role for ubiquitin impacts on Smad1/5 signaling and deregulates angiogenesis downstream of bone morphogenetic proteins, adding to the growing list of Met1-polyubiquitin-regulated cellular pathways.