Lipid-binding protein which promotes lipid absorption by facilitating MTTP-mediated lipid transfer (mainly triglycerides and phospholipids) and MTTP-mediated apoB lipoprotein assembly and secretion (By similarity). Protects the gastrointestinal epithelium from irradiation-induced apoptosis (By similarity). May play an important role in maintaining normal growth homeostasis in epithelial cells (PubMed:14583459). Involved in p53/TP53-dependent cell survival after DNA damage (PubMed:23235459). May down-regulate the expression of MAD1L1 and exert a suppressive role in mitotic spindle assembly checkpoint in hepatocellular carcinomas (PubMed:24374861).