MARCKS and schizophrenia: In schizophrenia there is reduced expression of MARCKS and phosphorylated MARCKS (pMARCKS).112 This is particularly interesting in the context of PTM-associated abnormalities in schizophrenia because MARCKS and PSA-NCAM interact via apposing sides of the plasma membrane to regulate actin cytoskeletal dynamics (Fig. 5).113 The respective glycan and lipid PTMs on these proteins appear to be necessary for proper interaction of their substrates.