Mediates the anchoring of the endoplasmic reticulum to microtubules. High-affinity epithelial cell surface receptor for the FZD8-related low molecular weight sialoglycopeptide APF/antiproliferative factor. Mediates the APF antiproliferative signaling within cells. Interacts with REEP5. Translocates to the perinuclear region upon APF-stimulation. Reversibly palmitoylated. Palmitoylation at Cys-100 by ZDHHC2 is required for its trafficking from the ER to the plasma membrane and for its perinuclear localization. Palmitoylation by ZDHHC2 is also required for its function in APF-mediated antiproliferative signaling (PubMed:19144824). Increased phosphorylation during mitosis prevents binding to microtubules. Aberrant splicing.