GATA‐4 interacts with the UCS domain of the Myosin Chaperone, Striated Muscle UNC‐45

Abstract

Striated muscle UNC‐45 (SM UNC‐45 or UNC‐45B) protein acts as a chaperone for cardiac and skeletal muscle myosins; regulating their folding, assembly into thick filaments, interaction with other sarcomeric proteins, and degradation. GATA‐4 is a transcription factor that regulates the expression of several cardiac muscle genes, including myosin. A previous study by Chen et al (2012) demonstrated for the first time that SM UNC‐45 (UNC‐45B) physically interacted with GATA‐4 and promoted its transcriptional activity in an overexpression experiment. The aim of this study was to identify the specific domain in UNC‐45B that interacted with GATA‐4. Pull‐down assays showed that GATA‐4 bound to the UCS domain of UNC‐45B. The major revelation from these studies is that UNC‐45B has the potential to exert both short‐term (protein level) and long‐term (gene level) controls over myosin and therefore muscle structure and function. Experiments are ongoing to determine whether UNC‐45B acts as a chaperone on GATA‐4 protein.Support or Funding InformationRobert A. Welch Foundation Grant #AN‐0008