SMG1 is a family of eukaryotic proteins. In humans this family acts as an mRNA-surveillance protein. In C.elegans, SMG1, a phosphatidylinositol kinase-related protein kinase, is a key regulator of growth. Loss of SMG1 leads to hyperactive responses to injury and subsequent growth that continues out of control. It has an antagonistic role to mTOR signalling in these worms and possibly also in higher eukaryotes.