Probe		Negative control
BAY-598		BAY-369

SET  and  MYND  domain-containing  protein  2  (SMYD2)  is  a member  of  the  SMYD  family  of  protein  methyltransferases.  All  five members of this family (SMYD1–5) contain a conserved catalytic SET domain and a zinc-finger MYND motif. SMYD2 methylates both histone and non-histone proteins, including p53/TP53 and RB1 [1-3]. It specifically methylates histone H3 'Lys-4' (H3K4me) and dimethylates histone H3 'Lys-36' (H3K36me2) [1]. It has relatively higher methyltransferase activity on p53/TP53 and monomethylates 'Lys-370' of p53/TP53, leading to decreased DNA-binding activity and subsequent transcriptional regulation activity of p53/TP53. SMYD2 is over-expressed in esophageal squamous primary carcinomas and that over-expression correlates with poor patient survival [2].

A collaboration between Bayer and the SGC has resulted in the discovery of BAY-598 [4], a potent, peptide-competitive chemical probe for SMYD2. BAY-598 has a unique chemotype relative to the current SMYD2 chemical probe LLY-507 [5] and inhibitors [6,7]. BAY-598 inhibits in vitro methylation of p53K370 with IC50 = 27 nM and has more than 100-fold selectivity over other histone methyltransferases and other non-epigenetic targets. BAY-598 inhibits the methylation of p53K370 in cells with IC50 < 1 µM. (Further to this, BAY-598 has properties that are compatible with in vivo experiments.) A control compound, BAY-369, has also been developed. BAY-369 inhibits the in vitro methylation of p53K370 with IC50 > 70 micromolar.