A complex that loads the DNA polymerase processivity factor proliferating cell nuclear antigen (PCNA) onto DNA, thereby permitting processive DNA synthesis catalyzed by DNA polymerase. In eukaryotes the complex consists of five polypeptides. [ http://www.ncbi.nlm.nih.gov/pubmed/16172520 http://www.ncbi.nlm.nih.gov/pubmed/14614842 http://www.ncbi.nlm.nih.gov/pubmed/14646196 ]