Fibronectin increases the force production of mouse papillary muscles via α5β1 integrin

► Fibronectin (FN) acts via α5β1 integrin to increase force production in myocardium. ► The force enhanced by FN relates to an increase in intracellular Ca2+ concentration. ► FN increases L-type Ca2+ channel currents in cardiomyocytes. ► FN-treated myocardium exhibits an increase in myofilament Ca2+ sensitivity. ► FN enhances contractility via PKA activation and phosphorylation of phospholamban.