The conformational change also switches LysRS activity from aminoacylation of Lysine tRNA to diadenosine tetraphosphate (Ap4A) production. Ap4A, which is an adenosine joined to another adenosine through a 5‘-5’tetraphosphate bridge, binds to HINT1 and this releases MITF from the inhibitory complex, allowing it to transcribe its target genes. Specifically, Ap4A causes a polymerization of the HINT1 molecule into filaments.
The conformational change also shifts LysRS activity from aminoacylation of lysine tRNA to diadenosine tetraphosphate (Ap4A) production. Ap4A, which is an adenosine joined to another adenosine through a 5‘-5’tetraphosphate bridge, binds to HINT1 and this releases MITF from the inhibitory complex, allowing it to transcribe its target genes. Specifically, Ap4A causes a polymerization of the HINT1 molecule into filaments.