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Histone acetyltransferase CBP promotes function of SCF FBXL19 ubiquitin E3 ligase by acetylation and stabilization of its F‐box protein subunit
Author(s) -
Wei Jianxin,
Dong Su,
Yao Kangning,
Martinez Maria Francesca Ysabelle M.,
Fleisher Paine R.,
Zhao Yutong,
Ma Haichun,
Zhao Jing
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.201701069r
Subject(s) - ubiquitin ligase , acetylation , ubiquitin , acetyltransferase , f box protein , proteasome , protein subunit , microbiology and biotechnology , histone acetyltransferase , histone h4 , chemistry , dna ligase , protein degradation , biology , biochemistry , enzyme , gene
Ubiquitin E3 ligases mediate ubiquitination and degradation of intracellular proteins. We have shown that a relatively new Skp, Cullin, F‐box (SCF) protein E3 ligase, SCF FBXL19, has an anti‐inflammatory effect and controls actin cytoskeleton dynamics via targeting cell membrane receptor and small GTPases for their ubiquitination and degradation, but the molecular regulation of its subunit FBXL19 stability remains unclear. Here we show that FBXL19 degradation is controlled by the balance between its ubiquitination and acetylation. FBXL19 is an unstable protein with a half‐life of ~3 h. FBXL19 can be polyubiquitinated, and the proteasome inhibitor MG‐132 prolongs FBXL19 half‐life, suggesting that FBXL19 degradation is mediated in the ubiquitin‐proteasome system. FBXL19 can also be acetylated, and enhancing acetylation of FBXL19 by a deacetylase inhibitor reduces FBXL19 ubiquitination levels. Acetylation‐mimic FBXL19 mutant exhibits a longer half‐life than wild type. An acetyl‐transferase CBP catalyzes acetylation of FBXL19. Inhibition or down‐regulation of CBP reduces FBXL19 stability, whereas it is increased in CBP‐overexpressing cells. Taken together, the data indicate that CBP‐mediated acety‐lation reduces ubiquitination and stabilizes FBXL19. Further, we demonstrate that FBXL19 targets small GTPase Cdc42 for its ubiquitination and degradation, whereas this effect is reversed by inhibition of CBP, suggesting that CBP increases the effect of SCF FBXL19 E3 ligase through acetylation and stabilization of FBXL19. Our study reveals a new molecular model for regulation of SCF E3 ligase function by acetylation and stabilization of its subunit F‐box protein.—Wei, J., Dong, S., Yao, K., Martinez M. F. Y. M., Fleisher, P. R., Zhao, Y., Ma, H., Zhao J. Histone acetyltransferase CBP promotes function of SCF FBXL19 ubiquitin E3 ligase by acetylation and stabilization of its F‐box protein subunit. FASEB J . 32, 4284–4292 (2018). www.fasebj.org