Component of the FACT complex, a general chromatin factor that acts to reorganize nucleosomes. The FACT complex is involved in multiple processes that require DNA as a template such as mRNA elongation, DNA replication and DNA repair. During transcription elongation the FACT complex acts as a histone chaperone that both destabilizes and restores nucleosomal structure. It facilitates the passage of RNA polymerase II and transcription by promoting the dissociation of one histone H2A-H2B dimer from the nucleosome, then subsequently promotes the reestablishment of the nucleosome following the passage of RNA polymerase II (By similarity). Forms a stable heterodimer with spt16 (By similarity). The spt16-pob3 dimer weakly associates with multiple molecules of nhp6 to form the FACT complex (By similarity). Interacts with abo1 (PubMed:26582768). Colocalizes with RNA polymerase II on chromatin. Recruited to actively transcribed loci. Sensitive to methyl methanesulfonate (DNA damaging agent). In contrast to the orthologous protein in animals and plants, this protein does not contain a HMG box DNA-binding domain. This function may instead be provided by the HMG box of the associated nhp6 protein in the FACT complex of fungi. Belongs to the SSRP1 family.