The GINS complex plays an essential role in the initiation of DNA replication, and progression of DNA replication forks. GINS4 is important for GINS complex assembly. 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. Forms a stable subcomplex with GINS1. GINS complex interacts with DNA primase in vitro. Component of the CMG helicase complex, composed of the MCM2-7 complex, the GINS complex and CDC45 (By similarity). Significantly up-regulated in aggressive melanomas. This is the measured mass for the GINS complex. Belongs to the GINS4/SLD5 family.