Titin based viscosity in ventricular physiology: An integrative investigation of PEVK-actin interactions

► Our goal was to study the role of titin-based viscosity in diastolic function. ► The titin PEVK element interacts in vitro with actin to create viscosity; we used a mouse deficient in PEVK. ► PEVK KO reduces viscosity > 50% in skinned tissue in vitro and > 30% in hearts in vivo. ► The PEVK-actin interaction is an important physiologic source of viscosity.