Histone acetyltransferase CBP promotes function of SCF FBXL19 ubiquitin E3 ligase by acetylation and stabilization of its F‐box protein subunit

Abstract

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 acetyltransferase 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 acetylation 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.

The effect of acetylation on the protein stability of BmApoLp‐III in the silkworm, Bombyx mori

“…Since nonhistone acetylation was first identified, increasingly more functions for acetylation have been found to act on various life processes, including DNA damage response and autophagy (Botrugno et al, 2012;Zhong et al, 2017;Yasuda et al, 2018), genomic stability (Billon et al, 2017;Fournier and Tora, 2017), transcriptional activity (Seo et al, 2015), protein degradation (Liu et al, 2013;Wei et al, 2018) and lysosomal function (Zhang et al, 2018). Previous studies have shown that acetylation could compete with ubiquitination at the same lysine residue, thus blocking the ubiquitin-mediated proteasomal degradation pathway to improve the protein stability, which is involved in cell cycle regulation (Lahusen et al, 2018), tumour suppression and progression (Wan et al, 2015;Choi et al, 2017), bacterial virulence (Sang et al, 2017) and signal transduction (Garcia-Aguilar et al, 2016;Beckwith et al, 2018;Wei et al, 2018). In our previous work, many acetylated sites were found on the nutrient storage proteins in the haemolymph of B. mori, including three storage proteins (SP1, SP2 and SP3), three apolipophorin proteins (BmApoLp-I, BmApoLp-II and BmApoLp-III) and six 30 K proteins (Nie et al, 2015).…”

Two distinct E3 ligases, SCFFBXL19and HECW1, degrade thyroid transcription factor 1 in normal thyroid epithelial and follicular thyroid carcinoma cells, respectively

“…FBXL19, a component of the SCF E3 ligase complex, can specifically recognize substrates for ubiquitination. We have demonstrated that FBXL19 exhibited antiinflammatory properties (33,35) and modulated small G protein stability (32,34,36). In this study, we showed that TTF1 is a new target of FBXL19 in FTC133 cells.…”

“…We have demonstrated that FBXL19 regulates IL-33 signaling by targeting its cognate receptor ST2L for ubiquitination (33). In addition to ST2L, we also found that CREB-binding protein (CBP), Rac family small GTPase 1 (Rac1), Rac family small GTPase 1 (Rac3) and Ras homolog gene family, member A (RhoA) are targets for FBXL19 (32,(34)(35)(36). Here, we verified TTF1 as a new target for FBXL19 in follicular thyroid carcinoma.…”

The stability and antiapoptotic activity of Bm30K‐3 can be improved by lysine acetylation in the silkworm, Bombyx mori

“…Recent studies have shown that the acetylation of many nonhistone proteins is associated with tumorigenesis, cancer cell proliferation, and immune function, which makes the regulation of protein acetylation a potential approach for the treatment of cancer (de Almeida Nagata et al, ; Dou, Zheng, Liu, & Tu, ; Liu, Li, Wu, & Cho, ). At present, acetylation has been shown to be involved in many important biological processes, including cell apoptosis (Cohen et al, ; S. S. Choi, Rhee, & Park, ), subcellular localization (Fujita, Fujiwara, Zenitani, & Yamashita, ; Ishfaq et al, ; Ito et al, ), DNA replication and repair (Al Emam, Arbon, Jeeves, & Kysela, ; Ghosh, Bohr, & Karmakar, ), DNA and protein interactions (Ugrinova, Pashev, & Pasheva, ), DNA transcription (Asano, Czuwara, & Trojanowska, ), protein stability (J. R. Choi, Lee, Shin, Choi, & Kang, ; J. Y. Choi, Ko, & Jo, ; Ge, Jin, Zhang, Yan, & Zhai, ; Wei et al, ), and so on. Regarding the regulation of protein stability, acetylation can compete with lysine ubiquitination and inhibit the proteasome degradation pathway mediated by ubiquitin, improving the stability and accumulation of proteins in cells that are involved in many physiological functions such as synaptic plasticity and cognitive function (G. Wang et al, ), tumor suppression (J. R. Choi et al, ), nuclear translocation, and transcriptional activity (Ge et al, ).…”

“…S. Choi, Rhee, & Park, 2002), subcellular localization (Fujita, Fujiwara, Zenitani, & Yamashita, 2015;Ishfaq et al, 2012;Ito et al, 2015), DNA replication and repair (Al Emam, Arbon, Jeeves, & Kysela, 2018;Ghosh, Bohr, & Karmakar, 2019), DNA and protein interactions (Ugrinova, Pashev, & Pasheva, 2009), DNA transcription (Asano, Czuwara, & Trojanowska, 2007), protein stability (J. R. Choi, Lee, Shin, Choi, & Kang, 2017;J. Y. Choi, Ko, & Jo, 2018;Ge, Jin, Zhang, Yan, & Zhai, 2009;Wei et al, 2018), and so on. Regarding the regulation of protein stability, acetylation can compete with lysine ubiquitination and inhibit the proteasome degradation pathway mediated by ubiquitin, improving the stability and accumulation of proteins in cells that are involved in many physiological functions such as synaptic plasticity and cognitive function (G. Wang et al, 2017), tumor suppression (J. R. Choi et al, 2017), nuclear translocation, and transcriptional activity (Ge et al, 2009).…”