Regulation of unfolded protein response modulator XBP1s by acetylation and deacetylation.

XBP1 (X-box-binding protein 1) is a key modulator of the UPR (unfolded protein response), which is involved in a wide range of pathological and physiological processes. The mRNA encoding the active spliced form of XBP1 (XBP1s) is generated from the unspliced form by IRE1 (inositol-requiring enzyme 1) during the UPR. However, the post-translational modulation of XBP1s remains largely unknown.

General transcription factor IIA-gamma increases osteoblast-specific osteocalcin gene expression via activating transcription factor 4 and runt-related transcription factor 2.

ATF4 (activating transcription factor 4) is an osteoblast-enriched transcription factor that regulates terminal osteoblast differentiation and bone formation. ATF4 knock-out mice have reduced bone mass (severe osteoporosis) throughout life. Runx2 (runt-related transcription factor 2) is a runt domain-containing transcription factor that is essential for bone formation during embryogenesis and postnatal life.