catalytic activity:NAD(+) + (ADP-D-ribosyl)(n)-acceptor = nicotinamide + (ADP-D-ribosyl)(n+1)-acceptor.,function:May regulate vesicle trafficking and modulate the subcellular distribution of SLC2A4/GLUT4-vesicles. Has PARP activity and can modify TERF1, and thereby contribute to the regulation of telomere length.,PTM:ADP-ribosylated (-auto).,PTM:Phosphorylated on serine residues by MAPK kinases upon insulin stimulation.,similarity:Contains 1 PARP catalytic domain.,similarity:Contains 1 SAM (sterile alpha motif) domain.,similarity:Contains 15 ANK repeats.,subcellular location:Associated with the Golgi and with juxtanuclear SLC2A4/GLUT4-vesicles. A minor proportion is also found at nuclear pore complexes and around the pericentriolar matrix of mitotic centromeres. During interphase, a small fraction of TNKS is found in the nucleus, associated with TERF1.,subunit: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.,tissue specificity:Ubiquitous; highest levels in testis.,