TY - JOUR TI - Molecular mechanism of Afadin substrate recruitment to the receptor phosphatase PTPRK via its pseudophosphatase domain AU - Hay, Iain M AU - Mulholland, Katie E AU - Lai, Tiffany AU - Graham, Stephen C AU - Sharpe, Hayley J AU - Deane, Janet E A2 - Hunter, Tony A2 - Cooper, Jonathan A A2 - Hunter, Tony A2 - Knapp, Stefan VL - 11 PY - 2022 DA - 2022/10/20 SP - e79855 C1 - eLife 2022;11:e79855 DO - 10.7554/eLife.79855 UR - https://doi.org/10.7554/eLife.79855 AB - Protein tyrosine phosphatase receptor-type kappa (PTPRK) is a transmembrane receptor that links extracellular homophilic interactions to intracellular catalytic activity. Previously we showed that PTPRK promotes cell–cell adhesion by selectively dephosphorylating several cell junction regulators including the protein Afadin (Fearnley et al, 2019). Here, we demonstrate that Afadin is recruited for dephosphorylation by directly binding to the PTPRK D2 pseudophosphatase domain. We mapped this interaction to a putative coiled coil (CC) domain in Afadin that is separated by more than 100 amino acids from the substrate pTyr residue. We identify the residues that define PTP specificity, explaining how Afadin is selectively dephosphorylated by PTPRK yet not by the closely related receptor tyrosine phosphatase PTPRM. Our work demonstrates that PTP substrate specificity can be determined by protein–protein interactions distal to the active site. This explains how PTPRK and other PTPs achieve substrate specificity despite a lack of specific sequence context at the substrate pTyr. Furthermore, by demonstrating that these interactions are phosphorylation-independent and mediated via binding to a non-catalytic domain, we highlight how receptor PTPs could function as intracellular scaffolds in addition to catalyzing protein dephosphorylation. KW - phosphatase KW - enzyme-substrate KW - cell adhesion KW - protein complex JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -