TATA-binding protein in neurodegenerative disease

TATA binding protein (TBP) is a general transcription factor that plays an important role in initiation of transcription. In recent years evidence has emerged implicating TPB in the molecular mechanism of a number of neurodegenerative diseases. Wild type TBP in humans contains a long polyglutamine stretch ranging in size from 29 to 42. It has been found associated with aggregated proteins in several of the polyglutamine disorders. Expansion in the CAA/CAG composite repeat beyond 42 has been shown to cause a cerebellar ataxia, SCA17. The involvement of such an important housekeeping protein in the disease mechanism suggests a major impact on the functioning of cells. The question remains, does TBP contribute to these diseases through a loss of normal function, likely to be catastrophic to a cell, or the gain of an aberrant function? This review deals with the function of TBP in transcription and cell function. The distribution of the polyglutamine coding allele lengths in TBP of the normal population and in SCA17 is reviewed and an outline is given on the reported cases of SCA17. The role of TBP in other polyglutamine disorders will be addressed as well as its possible role in other neurodegenerative diseases.