The function of SEC23IP (SEC23 interacting protein, Ensembl gene identifier ENSG00000107651) is as follows. Plays a role in the organization of endoplasmic reticulum exit sites. Specifically binds to phosphatidylinositol 3-phosphate (PI(3)P), phosphatidylinositol 4-phosphate (PI(4)P) and phosphatidylinositol 5-phosphate (PI(5)P). {ECO:0000269|PubMed:10400679, ECO:0000269|PubMed:15623529, ECO:0000269|PubMed:22922100}.