PQBP1 may suppress the ability of POU3F2 to transactivate the DRD1 gene in a POU3F2 dependent manner. It can activate transcription directly or via association with the transcription machinery. PQBP1 may be involved in ATXN1 mutant-induced cell death. The interaction with ATXN1 mutant reduces levels of phosphorylated RNA polymerase II large subunit. Defects in PQBP1 are the cause of Renpenning syndrome 1 (RENS1), also known as Sutherland-Haan X-linked mental retardation syndrome (SHS) or X-linked mental retardation syndromes MRXS3/MRXS8/MRX55. The clinical features are mental retardation, microcephaly, short stature, and small testes. The craniofacies tends to be narrow and tall with upslanting palpebral fissures, abnormal nasal configuration, cupped ears, and short philtrum. The nose may appear long or bulbous, with overhanging columella. Less consistent manifestations include ocular colobomas, cardiac malformations, cleft palate, and anal anomalies. RENS1 is more frequently in males than in females where little or no expression is found.
Alternate names: 38 kDa nuclear protein containing a WW domain, NPW38, PQBP-1, Polyglutamine tract- binding protein 1, Polyglutamine-binding protein 1