Deposition-and-exchange histone chaperone specific for H2AZ1, specifically chaperones H2AZ1 and deposits it into nucleosomes. As component of the SRCAP complex, mediates the ATP-dependent exchange of histone H2AZ1/H2B dimers for nucleosomal H2A/H2B, leading to transcriptional regulation of selected genes by chromatin remodeling. Component of the NuA4 histone acetyltransferase complex. Belongs to the VPS72/YL1 family.