Nine proteins were identified in the Co-IP from the entire SM patient group but not in the patient subgroups (Table 1), among them azurocidin, the N-terminal acetylated form, after M1 removal, of fatty acid-binding protein 5 (FABP-5), glutamine synthetase, junction plakoglobin, neutrophil defensin 1, plakophilin-1, and S100A8. Here, PKP1 is linked to systemic mastocytosis.