As part of the alternative replication protein A complex, aRPA, binds single-stranded DNA and probably plays a role in DNA repair. Compared to the RPA2-containing, canonical RPA complex, may not support chromosomal DNA replication and cell cycle progression through S-phase. The aRPA may not promote efficient priming by DNA polymerase alpha but could support DNA polymerase delta synthesis in the presence of PCNA and replication factor C (RFC), the dual incision/excision reaction of nucleotide excision repair and RAD51-dependent strand exchange. {ECO:0000269|PubMed:19116208, ECO:0000269|PubMed:19942684, ECO:0000269|PubMed:19996105, ECO:0000269|PubMed:20545304}. This is the function of Ensembl gene identifier ENSG00000204086 (RPA4, replication protein A4).