May be involved in mitogenic function of FGF1. 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. Highly expressed in heart, skeletal muscle and pancreas. Expressed at lower levels in brain. Also found in placenta, liver and kidney. The disease is caused by variants affecting the gene represented in this entry.