title: Structural basis for CARM1 inhibition by indole and pyrazole inhibitors.
abstract: CARM1 (co-activator-associated arginine methyltransferase 1) is a PRMT (protein arginine N-methyltransferase) family member that catalyses the transfer of methyl groups from SAM (S-adenosylmethionine) to the side chain of specific arginine residues of substrate proteins. This post-translational modification of proteins regulates a variety of transcriptional events and other cellular processes. Moreover, CARM1 is a potential oncological target due to its multiple roles in transcription activation by nuclear hormone receptors and other transcription factors such as p53. Here, we present crystal structures of the CARM1 catalytic domain in complex with cofactors [SAH (S-adenosyl-L-homocysteine) or SNF (sinefungin)] and indole or pyazole inhibitors. Analysis of the structures reveals that the inhibitors bind in the arginine-binding cavity and the surrounding pocket that exists at the interface between the N- and C-terminal domains. In addition, we show using ITC (isothermal titration calorimetry) that the inhibitors bind to the CARM1 catalytic domain only in the presence of the cofactor SAH. Furthermore, sequence differences for select residues that interact with the inhibitors may be responsible for the CARM1 selectivity against PRMT1 and PRMT3. Together, the structural and biophysical information should aid in the design of both potent and specific inhibitors of CARM1.
authors.affiliation: Bristol-Myers Squibb Research and Development, P.O. Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: John S
authors.initials: JS
authors.lastname: Sack
authors.forename: Sandrine
authors.initials: S
authors.lastname: Thieffine
authors.forename: Tiziano
authors.initials: T
authors.lastname: Bandiera
authors.forename: Marina
authors.initials: M
authors.lastname: Fasolini
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Duke
authors.forename: Lata
authors.initials: L
authors.lastname: Jayaraman
authors.forename: Kevin F
authors.initials: KF
authors.lastname: Kish
authors.forename: Herbert E
authors.initials: HE
authors.lastname: Klei
authors.forename: Ashok V
authors.initials: AV
authors.lastname: Purandare
authors.forename: Pamela
authors.initials: P
authors.lastname: Rosettani
authors.forename: Sonia
authors.initials: S
authors.lastname: Troiani
authors.forename: Dianlin
authors.initials: D
authors.lastname: Xie
authors.forename: Jay A
authors.initials: JA
authors.lastname: Bertrand
mesh_terms: D000595:Amino Acid Sequence; D020134:Catalytic Domain / Q000187:drug effects; D018360:Crystallography, X-Ray; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D007211:Indoles / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000187:drug effects; D011484:Protein-Arginine N-Methyltransferases / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D011720:Pyrazoles / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D007211:Indoles; D011720:Pyrazoles; C031280:pyrazole; D011484:Protein-Arginine N-Methyltransferases; C119966:coactivator-associated arginine methyltransferase 1