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. The FACT complex is required for expression of Hox genes. Component of the FACT complex, a stable heterodimer of dre4/spt16 and Ssrp. Interacts with TRL/GAGA. Colocalizes with RNA polymerase II on chromatin. Recruited to actively transcribed loci. Belongs to the peptidase M24 family. SPT16 subfamily. Although related to the peptidase M24 family, this protein lacks conserved active site residues suggesting that it may lack peptidase activity.