p63 supports aerobic respiration through hexokinase II

Abstract

Short p63 isoform, ΔNp63, is crucial for epidermis formation, and it plays a pivotal role in controlling the turnover of basal keratinocytes by regulating the expression of a subset of genes involved in cell cycle and cell adhesion programs. The glycolytic enzyme hexokinase 2 (HK2) represents the first step of glucose utilization in cells. The family of HKs has four isoforms that differ mainly in their tissue and subcellular distribution. The preferential mitochondrial localization of HK2 at voltage-dependent anion channels provides access to ATP generated by oxidative phosphorylation and generates an ADP/ATP recycling mechanism to maintain high respiration rates and low electron leak. Here, we report that ΔNp63 depletion in human keratinocytes impairs mitochondrial basal respiration and increases mitochondrial membrane polarization and intracellular reactive oxygen species. We show ΔNp63-dependent regulation of HK2 expression, and we use ChIP, validated by p63-Chip sequencing genomewide profiling analysis, and luciferase assays to demonstrate the presence of one p63-specific responsive element within the 15th intronic region of the HK2 gene, providing evidence of a direct interaction. Our data support the notion of ΔNp63 as a master regulator in epithelial cells of a combined subset of molecular mechanisms, including cellular energy metabolism and respiration. The ΔNp63-HK2 axis is also present in epithelial cancer cells, suggesting that ΔNp63 could participate in cancer metabolic reprogramming.p63 | HK2 | keratinocytes | oxidative metabolism | mitochondria

PFKFB3, a Direct Target of p63, Is Required for Proliferation and Inhibits Differentiation in Epidermal Keratinocytes

“…This correlated with reduced PFKFB3 protein in p63 knockdown nHEKs (Figure 1f). We found that p63 knockdown had a relatively greater effect on PFKFB3 protein expression than on the expression of HK2, which has previously been shown to be regulated by p63 in proliferating keratinocytes (Viticchie et al, 2015) (Figure S2a, S2b). Finally, upon examining a p63 ChIP-seq data set previously published by Kouwenhoven and colleagues (Kouwenhoven et al, 2010), we identified two potential p63 binding sites within the PFKFB3 gene.…”

“…Keratinocytes express HK1, and thus it is possible that HK1 could compensate for the reduced HK2 levels after p63 knockdown. Furthermore, metabolomics data from p63 knockdown keratinocytes demonstrate elevated levels of Glucose-6-phosphate and Fructose-6-phosphate in p63 knockdown cells (Viticchie et al, 2015), consistent with reduced PFK1 activity (Boada et al, 2000, Perez et al, 2000, Shirai et al, 2013). …”

“…Studies have also shown a role for p63 and p73 isoforms in regulating metabolism (Du et al, 2013, Rufini et al, 2012, Su et al, 2012, Venkatanarayan et al, 2015). Viticchie et al have recently demonstrated that p63 regulates mitochondrial homeostasis in proliferating keratinocytes through regulation of hexokinase 2 (HK2) (Viticchie et al, 2015); however, other mechanisms by which p63 may regulate metabolism in epidermis have not been investigated. It is also incompletely understood how glycolytic metabolism might regulate the proliferation/differentiation balance within the epidermis.…”

Vascular ageing and endothelial cell senescence: Molecular mechanisms of physiology and diseases

“…Metabolic regulation by p53 family appears a key function for their cancer-related but also ageing-related phenotype. All the three members promote mitochondrial respiration thought regulation of different metabolic enzymes, including the glutaminase 2 (Gls2) (Adamovich et al, 2014;Amelio et al, 2014b;Bellomaria et al, 2010Bellomaria et al, , 2012Giacobbe et al, 2013;He et al, 2013;Hu et al, 2010;Sharif et al, 2015;Simon et al, 2014;Velletri et al, 2013;Viticchie et al, 2015). Gls2 regulates glutamine utilization, supplying anaplerotic flux of substrates resulting in promotion of mitochondrial activity and ATP synthesis (Amelio et al, 2014a;Maniam et al, 2015).…”

FOXM1 regulates proliferation, senescence and oxidative stress in keratinocytes and cancer cells

“…Among the latter genes, p63 controls the expression of glutathione peroxidase (GPX, [27]), REgulated in development and DNA Damage Response 1 (REDD1, [28]), cytoglobin (CYB, [26]), hexokinaseII (HK, [25]) and glutaminase-2 (GLS2, [29]).…”