Requirement of Histone Methyltransferase SMYD3 for Estrogen Receptor-mediated Transcription

Abstract

SMYD3 is a SET domain-containing protein with histone methyltransferase activity on histone H3-K4. Recent studies showed that SMYD3 is frequently overexpressed in different types of cancer cells, but how SMYD3 regulates the development and progression of these malignancies remains unknown. Here, we report the previously unrecognized role of SMYD3 in estrogen receptor (ER)-mediated transcription via its histone methyltransferase activity. We demonstrate that SMYD3 functions as a coactivator of ER␣ and potentiates ER␣ activity in response to ligand. SMYD3 directly interacts with the ligand binding domain of ER and is recruited to the proximal promoter regions of ER target genes upon gene induction. Importantly, our chromatin immunoprecipitation analyses provide compelling evidence that SMYD3 is responsible for the accumulation of di-and trimethylation of H3-K4 at the induced ER target genes. Furthermore, RNA interference-directed down-regulation of SMYD3 reveals that SMYD3 is required for ER-regulated gene transcription in estrogen signaling pathway. Thus, our results identify SMYD3 as a new coactivator for ER-mediated transcription, providing a possible link between SMYD3 overexpression and breast cancer. Estrogen receptor (ER)3 ␣ is a member of the nuclear receptor superfamily and the primary biosensor for estrogen (1, 2). Upon activation by estrogen, ER binds to specific DNA sequences called estrogen response elements (EREs) to induce expression of a number of target genes in specific organs, including the female reproductive organs, the central nervous system, and bone (1, 3, 4). ER is comprised of several structural domains that are highly conserved in the various nuclear receptors: the N-terminal transcription activation domain, the DNA binding domain, the hinge region, and the C-terminal conserved ligand binding domain (5-7). Like other nuclear receptors, the ER collaborates with a number of transcriptional cofactors to effectively modulate transcription of its target genes (3, 8 -10). These cofactors appear to regulate the chromatin configuration in a highly specific manner by controlling nucleosomal rearrangement and histone modifications at the promoter (11-13). This targeted alteration of chromatin structure allows the transcriptional machinery to access the chromatin DNA and form functional preinitiation complexes, thereby facilitating transcription initiation (14 -16).Two major types of chromatin remodeling have been widely investigated for ER transcription. The remodeling activities include the ATP-dependent chromatin remodeling factors, which alter structure and position of nucleosomes at the promoters of ER target genes. These include proteins such as brahma-related BRG1 (also known as hBRG1 or hSNF2) and BRM, both of which are subunits of the mammalian homologue of the yeast SWI/SNF complex (17, 18). The second class of remodeling factors includes a diverse group of single/multisubunit factors that effect post-translational modifications of the histone tails protruding from the surface of the nucl...

Effect of SMYD3 on the microRNA expression profile of MCF-7 breast cancer cells

“…5A). Consistently, SMYD3-ΔNHSC, a histone methyltransferase-activity-depleted mutant of SMYD3 (58,59), also decreases the transcription level of miR-200c-3p (Fig. 5B).…”

An Evolutionarily Conserved Innate Immunity Protein Interaction Network

“…The kinesin KIF21A is a plus-end-directed microtubule motor (97) that has not been implicated in innate immunity previously. set-18/Smyd3 mutant nematodes were slightly susceptible to pathogenic bacteria but not heat-killed E. coli; SMYD3 is a histone methyltransferase that affects transcription (98,99) and could therefore have many conceivable effects on innate immunity. Although the nematode siah-1/Siah1 mutation did not affect survival of the presence of P. aeruginosa, we note that there are many other pathogens that infect nematodes that we have not tested.…”

Regulation of estrogen receptor α by histone methyltransferase SMYD2-mediated protein methylation

“…The SMYD family protein SMYD3 has been shown to methylate H3K4 at the promoters of ERα target genes (23). Because SMYD2 can methylate both histone H3K4 and ERα-K266, we next sought to determine whether the increase of ERα occupancy in SMYD2-knockdown cells is due to the loss of ERα-K266 methylation or the loss of H3K4 methylation.…”