Transcription initiation protein SPT3 homolog is a protein that in humans is encoded by the SUPT3H gene.
Transcription initiation protein SPT3 homolog has been shown to interact with GCN5L2, TAF6L, TADA3L, TAF5L, SF3B3, SUPT7L, Myc, TAF9, Transformation/transcription domain-associated protein, TAF12, TAF10, TAF4 and DDB1.