Enables phosphatidylinositol-3-phosphate binding activity. Acts upstream of or within protein lipidation involved in autophagosome assembly; protein localization to phagophore assembly site; and xenophagy. Located in autophagosome and phagophore assembly site. Is expressed in cranial ganglion; dorsal root ganglion; submandibular gland primordium; telencephalon; and vibrissa epidermal component. Orthologous to human WIPI2 (WD repeat domain, phosphoinositide interacting 2). [provided by Alliance of Genome Resources, Apr 2022]