Fig. 6: A working model proposing how the DNAJA2/HSC70 chaperone complex regulates CSB proteolysis and TC-NER. | Cell Discovery

Fig. 6: A working model proposing how the DNAJA2/HSC70 chaperone complex regulates CSB proteolysis and TC-NER.

From: Heat shock protein DNAJA2 regulates transcription-coupled repair by triggering CSB degradation via chaperone-mediated autophagy

Fig. 6

Upon UV irradiation, a transcription-blocking lesion is recognized by Pol II, which recruits CSB and CSA to the lesion to facilitate lesion recognition and stimulates sumoylation of CSB at its N-terminal domain. This sumoylation leads to a conformation change in CSB, making its KFERQ-like motif accessible to the DNAJA2/HSC70 chaperone complex, which binds to CSB (a). The DNAJA2/HSC70 complex exports CSB from nucleus to cytosol, where CSB undergoes lysosome degradation through LAMP2A-mediated CMA (b). The timely removal and degradation of CSB from the lesion permits Pol II to undertake a 5′-3′ translocation, also called backtracking, which makes the lesion available for verification by the downstream factor TFIIH and repair complex assembly to complete TC-NER (c).

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