Cell division cycle and apoptosis regulator protein 1 (CCAR1) associates with components of the Mediator and p160 coactivator complexes that play a role as intermediaries transducing regulatory signals from upstream transcriptional activator proteins to basal transcription machinery. CCAR1 also functions as a p53 coactivator and regulates expression of key proliferation-inducing genes [].Cell cycle and apoptosis regulator protein 2 (CCAR2, also known as DBC-1) regulates biological processes such as transcription, heterochromatin formation, metabolism, mRNA splicing, apoptosis, and cell proliferation []. It is a core component of the DBIRD complex, which affects local transcript elongation rates and alternative splicing of a large set of exons embedded in (A + T)-rich DNA regions []. It binds to SIRT1 and is a negative regulator of SIRT1 []. DBC-1 has been implicated in tumorigenesis [].This entry also includes protein SHORT ROOT IN SALT MEDIUM 1 (RSA1, also known as EMB1579) from Arabidopsis. It regulates the transcription of several genes involved in the detoxification of reactive oxygen species generated by salt stress and the SOS1 gene that encodes a plasma membrane Na(+)/H(+) antiporter essential for salt tolerance []. RSA1 is localised to the nucleus and the loss of function of RSA1 affects global transcription and mRNA splicing [].
