Component of the autophagy machinery that controls the major intracellular degradation process by which cytoplasmic materials are packaged into autophagosomes and delivered to lysosomes for degradation (PubMed:23435086, PubMed:28561066). Binds phosphatidylinositol 3- phosphate (PtdIns3P) (PubMed:28561066). Activated by the STK11/AMPK signaling pathway upon starvation, WDR45 is involved in autophagosome assembly downstream of WIPI2, regulating the size of forming autophagosomes (PubMed:28561066). Together with WIPI1, promotes ATG2 (ATG2A or ATG2B)-mediated lipid transfer by enhancing ATG2-association with phosphatidylinositol 3-monophosphate (PI3P)-containing membranes (PubMed:31271352). Probably recruited to membranes through its PtdIns3P activity (PubMed:28561066). {ECO:0000269|PubMed:23435086, ECO:0000269|PubMed:28561066, ECO:0000269|PubMed:31271352}. This is the function of ENSG00000196998 (WDR45, WD repeat domain 45).