dystrophia myotonica protein kinase (dmpk) is a serine/threonine kinase composed of a kinase domain and a coiled-coil domain involved in the multimerization. the crystal structure of the kinase domain of dmpk bound to the inhibitor bisindolylmaleimide viii (bim-8) revealed a dimeric enzyme associated by a conserved dimerization domain. the affinity of dimerisation suggested that the kinase domain alone is insufficient for dimerisation in vivo and that the coiled-coil domains are required for stable dimer formation. the kinase domain is in an active conformation, with a fully ordered and correctly positioned ac helix, and catalytic residues in a conformation competent for catalysis. the conserved hydrophobic motif at the c-terminal extension of the kinase domain is bound to the n-terminal lobe of the kinase domain, despite being unphosphorylated.