Acts as a transcriptional coactivator in Wg signaling caused by altered arm signaling. Pont and rept interfere antagonistically with nuclear arm signaling function, and are required to enhance or reduce arm activity, respectively. Also an essential cofactor for the normal function of Myc; required for cellular proliferation and growth. Proposed core component of the chromatin remodeling Ino80 complex which is involved in transcriptional regulation, DNA replication and probably DNA repair. ATP + H2O = ADP + H(+) + phosphate Forms homohexameric rings. May form a dodecamer with rept made of two stacked hexameric rings (By similarity). Component of the chromatin remodeling Ino80 complex. Interacts with Myc and rept. Higher expression occurs in primordia of mesoderm, anterior and posterior midgut and cephalic furrow early in gastrulation, as well as in endoderm and mesoderm lineages during germ band extension. Later in development expression is only maintained in endoderm cells. Expressed in thoracic and abdominal segment neural precursors of all embryonic chordotonal organs. Expressed both maternally and zygotically. Death at first larval instar. Belongs to the RuvB family.