Peptidylarginine deiminase 2-catalyzed histone H3 arginine 26 citrullination facilitates estrogen receptor α target gene activation

Abstract

Cofactors for estrogen receptor α (ERα) can modulate gene activity by posttranslationally modifying histone tails at target promoters. Here, we found that stimulation of ERα-positive cells with 17β-estradiol (E2) promotes global citrullination of histone H3 arginine 26 (H3R26) on chromatin. Additionally, we found that the H3 citrulline 26 (H3Cit26) modification colocalizes with ERα at decondensed chromatin loci surrounding the estrogen-response elements of target promoters. Surprisingly, we also found that citrullination of H3R26 is catalyzed by peptidylarginine deiminase (PAD) 2 and not by PAD4 (which citrullinates H4R3). Further, we showed that PAD2 interacts with ERα after E2 stimulation and that inhibition of either PAD2 or ERα strongly suppresses E2-induced H3R26 citrullination and ERα recruitment at target gene promoters. Collectively, our data suggest that E2 stimulation induces the recruitment of PAD2 to target promoters by ERα, whereby PAD2 then citrullinates H3R26, which leads to local chromatin decondensation and transcriptional activation. C ancers of the female reproductive system are serious human health problems, and estrogen plays a critical role in the initiation and progression of these diseases (1). Despite decades of research into mechanisms of 17β-estradiol (E2)-responsive gene transcription, our understanding of this process is far from complete (2). It is generally believed that, upon E2 binding, the nuclear hormone receptor estrogen receptor α (hereafter called ER) undergoes major structural reorganization, associates with estrogen-response elements (ERE) within target gene promoters, and recruits a range of coactivators including histone modification enzymes (3-6). After deposition, the resulting histone modifications can then modulate target gene activity by affecting local chromatin structure and regulating the accessibility of chromatin to transcription factors (2, 5, 7-9).Peptidylarginine deiminase (PAD) enzymes convert arginine and methylarginine residues to citrulline via a hydrolytic process termed citrullination or deimination (10, 11). We and others have shown that one such PAD, PAD4, appears to play a repressive role in regulating the expression of the canonical ER target gene, TFF1, via citrullination of histone H4 methylarginine 3, thus suggesting that PADs potentially function as ER cofactors (12, 13). Given that these previous studies were limited to a single ER target promoter, we chose to take a more comprehesive approach to test whether PAD-mediated histone tail citrullination may be more fundamental to ER target gene regulation than previously realized. In this study, we show that citrullination of histone H3R26 at ER targets is closely associated with gene transcription and that citrullination at this residue is catalyzed by PAD2, as opposed to PAD4. Additionally, we show that PAD2 interacts with ER and that PAD2-mediated citrullination of H3R26 likely facilitates transcriptional activation by creating an open, permissive, chromatin architecture around the EREs of E2-i...

PAD2 Overexpression in Transgenic Mice Promotes Spontaneous Skin Neoplasia

“…In addition, we found strong nuclear anti-pan-citrulline staining in these lesions (Fig. 2D, inset bottom image), which is in line with our previous studies showing that PAD2-mediated histone deimination regulates gene expression (9,10,14,21). Because the anti-human PAD2 antibody likely cross-reacts with endogenous mouse PAD2, we also stained these tissues with an anti-FLAG antibody to specifically stain the PAD2 fusion protein.…”

“…To generate the MMTV-FLAG-PAD2 construct, human PAD2 cDNA was subcloned from pcDNA3.1-FLAG-PAD2 (14) into the EcoRI sites of the MMTV-SV40-Bssk plasmid (Addgene plasmid #1824), originally generated in the laboratory of Dr. Philip Leder at Harvard Medical School (Boston, MA; ref. 15).…”

Clipping of arginine-methylated histone tails by JMJD5 and JMJD7

“…First, methyl groups may be removed directly from arginine by demethylation, similar to mechanisms used by JmjC proteins to demethylate methyl lysine (27). Second, methylated arginine may be converted to citrulline, similar to the products of peptidylarginine deiminase (PADI) enzymes (27)(28)(29)(30). Third, methyl arginine may be removed by more extensive cleavage of histone tails by proteolysis, thus using a clipping process (3).…”

Arginine methylation and citrullination of splicing factor proline- and glutamine-rich (SFPQ/PSF) regulates its association with mRNA

“…For example, PADI4 catalyzed deimination of histone H3 at Arg17 and histone H4 at Arg 3 has been linked to transcriptional repression (Cuthbert et al 2004;Wang et al 2004). Conversely, citrullination of histone H3R26 by PADI2 has been shown to facilitate transcriptional activation at target genes (Zhang et al 2012). More recently, Christophorou et al (2014) have demonstrated that citrullination of histone H1 leads to chromatin decondensation during pluripotency.…”