Transcriptional regulator that binds to the GA element of the CLCNKA promoter (By similarity). Binds to the KCNIP2 promoter and regulates KCNIP2 circadian expression in the heart. Is a repressor of CCN2 expression, involved in the control of cardiac fibrosis. Is also involved in the control of cardiac hypertrophy acting through the inhibition of MEF2A, GATA4 and MYOCD activity. Is a negative regulator of TP53 acetylation. Inhibits NF-kappa-B activation through repression of EP300-dependent RELA acetylation (By similarity). Involved in podocyte differentiation. Interacts with MYOCD. Interacts with EP300 (By similarity). Expressed in aortic smooth muscle cells. In the heart, up-regulated by the CLOCK/ARNTL heterodimer. 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 null mice are viable, but in response to pressure overload, they develop cardiac hypertrophy and fibrosis. Belongs to the Sp1 C2H2-type zinc-finger protein family.