Light-dependent and circadian clock-regulated activation of sterol regulatory element-binding protein, X-box-binding protein 1, and heat shock factor pathways.

The circadian clock is phase-delayed or -advanced by light when given at early or late subjective night, respectively. Despite the importance of the time-of-day-dependent phase responses to light, the underlying molecular mechanism is poorly understood. Here, we performed a comprehensive analysis of light-inducible genes in the chicken pineal gland, which consists of light-sensitive clock cells representing a prototype of the clock system.

BPOZ-2 directly binds to eEF1A1 to promote eEF1A1 ubiquitylation and degradation and prevent translation.

Bood POZ containing gene type 2 (BPOZ-2), which contains ankyrin repeats, NLS, BTB/POZ domains and LXXLL motifs, is an adaptor protein for the E3 ubiquitin ligase scaffold protein CUL3. We isolated a cDNA encoding eukaryotic elongation factor 1A1 (eEF1A1) as a BPOZ-2 binding protein by screening a human thymus cDNA library using a yeast two-hybrid system. eEF1A1 is essential for translation and is also involved in the 26S proteasome-dependent degradation of misfolded or unfolded proteins.