The plant and fungal cell wall is a key structure that serves as a physical boundary, a transducer of extracellular forces and signals, and coordinator of cellular growth. The state of the budding yeast cell wall is coupled to the progression of the cell cycle, and the cell wall integrity (CWI) checkpoint monitors wall remodelling to stall the cell cycle if needed. Whereas a role for the mitotic cyclin Clb2 and the dynactin complex in the CWI checkpoint has been shown, the majority of factors that control the checkpoint response remain to be identified. In their Research Article (Sukegawa et al., 2018), Yoshikazu Ohya and co-workers find additional components of the yeast cell wall integrity checkpoint. The authors demonstrate that components of the Las17 complex, as well as both the high osmolarity glycerol (HOG) and CWI MAPK pathways function in the checkpoint. Specifically, the defects that are caused by deletion of the Las17 or dynactin complexes can be rescued by hyperactivation of the CWI MAPK pathway, suggesting that the latter works downstream of Lis17 or dynactin. These data reveal the role of signalling pathways in the CWI checkpoint and establish its regulatory hierarchy.
