Identification of proximal SUMO-dependent interactors using SUMO-ID

To study the function of SUMOylation and SUMO-SIM interactions for particular substrates poses several challenges. SUMOylation occurs transiently and often in a small percentage of the total copy numbers of a given substrate. Modified proteins can be readily deSUMOylated and SUMO can be recycled and passed to other substrates. SUMO-SIM interactions are also difficult to analyze due to their weak affinity (Kd 1-100 µM). To overcome these technical issues, we developed SUMO-ID, a new strategy based on Split-TurboID to identify SUMO- interactors of specific substrates dependent on SUMO conjugation or interaction. Here we present SUMO-ID, a technology that merges proximity biotinylation by TurboID and protein-fragment complementation to find SUMO-dependent interactors. , the high sensitivity of SUMO-ID allowed to identify novel interactors of SUMOylated SALL1, a less characterized SUMO substrate.