Poly-ADP-ribosyltransferase involved in various processes such as Wnt signaling pathway, telomere length and vesicle trafficking. Acts as an activator of the Wnt signaling pathway by mediating poly-ADP-ribosylation of AXIN1 and AXIN2, 2 key components of the beta-catenin destruction complex: poly-ADP-ribosylated target proteins are recognized by RNF146, which mediates their ubiquitination and subsequent degradation. Also mediates poly-ADP-ribosylation of BLZF1 and CASC3, followed by recruitment of RNF146 and subsequent ubiquitination. Mediates poly-ADP-ribosylation of TERF1, thereby contributing to the regulation of telomere length. Stimulates 26S proteasome activity. NAD(+) + (ADP-D-ribosyl)n-acceptor = nicotinamide + (ADP-D-ribosyl)n+1-acceptor + H(+). L-aspartyl-[protein] + NAD(+) = 4-O-(ADP-D-ribosyl)-L-aspartyl-[protein] + nicotinamide L-glutamyl-[protein] + NAD(+) = 5-O-(ADP-D-ribosyl)-L-glutamyl-[protein] + nicotinamide Oligomerizes and associates with TNKS. Interacts with the cytoplasmic domain of LNPEP/Otase in SLC2A4/GLUT4-vesicles. Binds to the N-terminus of Grb14 and TRF1 with its ankyrin repeat region. Interacts with HIF1AN. Interacts with RNF146; this interaction leads to ubiquitination and proteasomal degradation. Interacts with NUMA1 (By similarity). Associated with the Golgi and with juxtanuclear SLC2A4/GLUT4-vesicles (By similarity). Also found around the pericentriolar matrix of mitotic centromeres (By similarity). During interphase, a small fraction of TNKS2 is found in the nucleus, associated with TRF1 (By similarity). Ubiquitinated by RNF146 when auto-poly-ADP-ribosylated, leading to its degradation. ADP-ribosylated (-auto). Poly-ADP-ribosylated protein is recognized by RNF146, followed by ubiquitination. Belongs to the ARTD/PARP family.