CDK1 and neuroblastoma: Phosphorylation of Ascl1 on six SP sites (S62, S88, S185, S189, S202, and S218) by proline-directed serine-threonine kinases (e.g., ERK, GSK3, and CDK1; Figure 1A) has so far only been demonstrated in transfected HEK293 (Li et al., 2014), neuroblastoma (Woods et al., 2022), and glioblastoma (Azzarelli et al., 2022) cells in vitro.