The STK2 gene, which encodes a putative Ser/Thr protein kinase, is required for high-affinity spermidine transport in Saccharomyces cerevisiae.
Kaouass M, Audette M, Ramotar D, Verma S, De Montigny D, Gamache I, Torossian K, Poulin R. Mol Cell Biol. 1997 Jun; 17(6):2994-3004.