The RET gene encodes a receptor tyrosine kinase that is expressed in nephric duct cells and displayed on the plasma membrane (inferred from mouse embryos). RET on the nephric duct interacts with GDNF secreted by the metanephric mesenchyme to regulate formation of the ureteric bud. Expression of RET is activated in the nephric duct by the transcription factors GATA3 (inferred from mouse homologs in Grote et al. 2006, Grote et al. 2008, Chia et al. 2011) and EMX2 (inferred from mouse homologs in Miyamoto et al. 1997) and the morphogen retinoic acid produced by the retinal dehydrogenase ALDH1A2 (also called RALDH2) (inferred from mouse homologs in Chia et al. 2011). In mouse organoids produced from cultured ureteric bud cells, enforced expression of Ret causes cells to cluster and form new ureteric buds (Packard et al. 2021).