F-Box and Leucine-Rich Repeat Protein 22 Is a Cardiac-Enriched F-Box Protein That Regulates Sarcomeric Protein Turnover and Is Essential for Maintenance of Contractile Function In Vivo

Abstract

These findings reveal the previously uncharacterized cardiac-specific F-box protein Fbxl22 as a component of a novel cardiac E3 ligase. Fbxl22 promotes the proteasome-dependent degradation of key sarcomeric proteins, such as α-actinin and filamin C, and is essential for maintenance of normal contractile function in vivo.