May be involved in mitogenic function of FGF1. May mediate with IER2 FGF-signaling in the establishment of laterality in the embryo (By similarity). {ECO:0000250|UniProtKB:Q6T938, ECO:0000269|PubMed:9806903}. This is the function of ENSG00000172500 (FIBP, FGF1 intracellular binding protein).