Poly-ADP-ribosyltransferase involved in various processes such as Wnt signaling pathway, telomere length and vesicle trafficking (PubMed:10988299, PubMed:11739745, PubMed:16076287, PubMed:19759537, PubMed:21478859, PubMed:22864114, PubMed:23622245, PubMed:25043379). Acts as an activator of the Wnt signaling pathway by mediating poly-ADP-ribosylation (PARsylation) 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 (PubMed:19759537, PubMed:21478859). Also mediates PARsylation of BLZF1 and CASC3, followed by recruitment of RNF146 and subsequent ubiquitination (PubMed:21478859). Mediates PARsylation of TERF1, thereby contributing to the regulation of telomere length (PubMed:11739745). Involved in centrosome maturation during prometaphase by mediating PARsylation of HEPACAM2/MIKI (PubMed:22864114). May also regulate vesicle trafficking and modulate the subcellular distribution of SLC2A4/GLUT4-vesicles (PubMed:10988299). May be involved in spindle pole assembly through PARsylation of NUMA1 (PubMed:16076287). Stimulates 26S proteasome activity (PubMed:23622245). 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 Specifically inhibited by XAV939, a small molecule, leading to inhibit the Wnt signaling pathway by stabilizing AXIN1 and AXIN2. Oligomerizes and associates with TNKS2. Interacts with the cytoplasmic domain of LNPEP/Otase in SLC2A4/GLUT4-vesicles. Binds to the N-terminus of telomeric TERF1 via the ANK repeats. Found in a complex with POT1; TERF1 and TINF2 (PubMed:12768206). Interacts with AXIN1 (PubMed:19759537, PubMed:21478859, PubMed:21799911). Interacts with AXIN2 (PubMed:19759537, PubMed:21478859). Interacts with BLZF1 and CASC3 (PubMed:21478859). Interacts with NUMA1 (PubMed:12080061). Associated with the Golgi and with juxtanuclear SLC2A4/GLUT4-vesicles (PubMed:22864114). A minor proportion is also found at nuclear pore complexes and around the pericentriolar matrix of mitotic centromeres (PubMed:10523501). During interphase, a small fraction of TNKS is found in the nucleus, associated with TERF1 (PubMed:12768206). Localizes to spindle poles at mitosis onset via interaction with NUMA1 (PubMed:12080061). Ubiquitous; highest levels in testis. Phosphorylated on serine residues by MAPK kinases upon insulin stimulation. Phosphorylated during mitosis. 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.