The role of GRP94 and its homologs is essential in organismal development as the deletion of the Drosophila Gp93 gene leads to growth defects (Maynard et al., 2010); Grp94 knockdown in mice causes embryonic lethality (Mao et al., 2010), and leads to impaired glucose tolerance (Kim et al., 2018), type 2 diabetes (Ghiasi et al., 2019) and defects in the trafficking of the HER2 (Erbb2) oncogene (Patel et al., 2013). The gene discussed is ERBB2; the disease is type 2 diabetes mellitus.