Required for correct functioning of the GINS complex, a complex that plays an essential role in the initiation of DNA replication, and progression of DNA replication forks. GINS complex seems to bind preferentially to single-stranded DNA. Component of the GINS complex which is a heterotetramer of GINS1, GINS2, GINS3 and GINS4 (PubMed:17545466, PubMed:17557111, PubMed:17652513, PubMed:28414293). Forms a stable subcomplex with GINS4. GINS complex interacts with DNA primase in vitro (PubMed:17545466, PubMed:17557111, PubMed:17652513, PubMed:28414293). Component of the CMG helicase complex, composed of the MCM2-7 complex, the GINS complex and CDC45 (By similarity). Associates with chromatin. Significantly up-regulated in aggressive melanomas. This is the measured mass for the GINS complex. The disease is caused by variants affecting the gene represented in this entry. Belongs to the GINS1/PSF1 family.