PPP1R9B and obesity due to melanocortin 4 receptor deficiency: To begin to understand how obesity impacts the pancreatic spinophilin protein interactome, we immunoprecipitated spinophilin from whole pancreas of control and Leprdb/db mice, and performed a “GelC-MS” proteomics approach where we excised spinophilin immunoprecipitates from a Coomassie-stained gel.