May be involved in mitogenic function of FGF1 (By similarity). May mediate with IER2 FGF-signaling in the establishment of laterality in the embryo (By similarity). Binds to internalized FGF1; this interaction is increased in the presence of CSNKB, suggesting a possible cooperative interaction between CSNKB and FIBP in binding to FGF1. Also associated with cytoplasmic membranes, particularly of mitochondria.