May function as a molecular transmitter linking various signaling pathways to transcriptional regulation. Negatively regulates the transcriptional repressor E4F1 and may function in cell growth. Inhibits the transcriptional activity of FOXO1 and its apoptotic function by enhancing the interaction of FOXO1 with SIRT1 and FOXO1 deacetylation. Negatively regulates the calcineurin/NFAT signaling pathway in cardiomyocytes (PubMed:28717008). Interacts with ZNF638 and TTN/titin (PubMed:11813260, PubMed:12432079). Interacts with E4F1 (PubMed:16652157). Interacts with GRB7 (PubMed:18853468). Interacts with SIRT1 and FOXO1 (PubMed:15692560). Interacts with CEFIP (PubMed:28717008). Interacts with calcineurin (By similarity). Interacts with FOXK1 (By similarity). Expressed in skeletal muscle and heart. The third LIM zinc-binding mediates interaction with E4F1.