Non-catalytic subunit of the tRNA-specific adenosine-34 deaminase complex, composed of the ADAT2 catalytic subunit and the ADAT3 regulatory subunit, which deaminates adenosine-34 (the first, also called wobble position of the anticodon) to inosine in many tRNAs. Inosine-34 allows the decoding of 3 different nucleotides at the third position of mRNA codons, as inosine is able to pair with U, C, and A. Required for binding of the ADAT2-ADAT3 complex to tRNA through its N- terminus, which rotates with respect to the catalytic domain of the complex, formed by ADAT2 and the ADAT3 C-terminal domain, to position the tRNA anticodon stem-loop correctly in the ADAT2 active site. The ADAT2-ADAT3 complex is required for radial migration of projection neurons in the developing brain cortex, and the catalytic activity of the complex is necessary for this function. . This is the function of ADAT3 (adenosine deaminase tRNA specific 3, Ensembl gene identifier ENSG00000213638).