The function of MPP3 (MAGUK p55 scaffold protein 3, ENSG00000161647) is as follows. Participates in cell spreading through the phosphoinositide- 3-kinase (PI3K) pathway by connecting CADM1 to DLG1 and the regulatory subunit of phosphoinositide-3-kinase (PI3K) (PubMed:24503895). Stabilizes HTR2C at the plasma membrane and prevents its desensitization. May participates in the maintenance of adherens junctions (By similarity). {ECO:0000250|UniProtKB:O88910, ECO:0000269|PubMed:24503895}.