Transcriptional regulator that binds to the GA element of the CLCNKA promoter. Binds to the KCNIP2 promoter and regulates KCNIP2 circadian expression in the heart (By similarity). Is a repressor of CCN2 expression, involved in the control of cardiac fibrosis. It is also involved in the control of cardiac hypertrophy acting through the inhibition of MEF2A and GATA4 (By similarity). Involved in podocyte differentiation (By similarity). Inhibits MYOCD activity. Is a negative regulator of TP53 acetylation. Inhibits NF-kappa-B activation through repression of EP300-dependent RELA acetylation. Interacts with MYOCD and EP300. Highly expressed in liver, skeletal muscle, and kidney. Expressed in cardiomyocytes. Expression is highly reduced in cardiac tissue of patients with non-ischemic cardiomyopathy and aortic aneurysm, and in glomerular disease. Not expressed in bone marrow or lymphoid tissues. In podocytes, up-regulated by retinoic acid. The 9aaTAD motif is a transactivation domain present in a large number of yeast and animal transcription factors. KLF15 deficiency results in loss of rhythmic QT variation and abnormal heart repolarization (PubMed:22367544). It may play a role in susceptibility to ventricular arrhythmias (PubMed:22367544), and development of pathological cardiac hypertrophy leading to heart failure (PubMed:20375365). Belongs to the Sp1 C2H2-type zinc-finger protein family.