Binds to the ANK repeat domain of TNKS1 and TNKS2. Colocalizes with chromosomes during mitosis, and in the cytoplasm with cortical actin. Detected in testis, ovary, lung, skeletal muscle, heart, prostate and pancreas, and at very low levels in brain and peripheral blood leukocytes. ADP-ribosylated by TNKS1 (in vitro). Extended N-terminus.