We have been working on the proteins that is located in the lysosomal membrane. We are looking for a method that can identify the binding partners of our proteins within the lysosome. The thing here is, the pH inside the lysosome is acidic and if we do IP, the binding will be lost due to the fact that IP will work well on neutral pH. We also tried using BirA tagged with targeted proteins, however, it seems interfere with the localization of the proteins in lysosome. Should we use longer linker sequence (between targeted gene and BirA), or any other methods that we can use? Thanks