Phosphorylation of neuronal Lysine‐Specific Demethylase 1LSD1/KDM1A impairs transcriptional repression by regulating interaction with CoREST and histone deacetylases HDAC1/2

Abstract

Epigenetic mechanisms play important roles in brain development, orchestrating proliferation, differentiation, and morphogenesis. Lysine-Specific Demethylase 1 (LSD1 also known as KDM1A and AOF2) is a histone modifier involved in transcriptional repression, forming a stable core complex with the corepressors corepressor of REST (CoREST) and histone deacetylases (HDAC1/2). Importantly, in the mammalian CNS, neuronal LSD1-8a, an alternative splicing isoform of LSD1 including the mini-exon E8a, sets alongside LSD1 and is capable of enhancing neurite growth and morphogenesis. Here, we describe that the morphogenic properties of neuronal LSD1-8a require switching off repressive activity and this negative modulation is mediated in vivo by phosphorylation of the Thr369b residue coded by exon E8a. Three-dimensional crystal structure analysis using a phospho-mimetic mutant (Thr369bAsp), indicate that phosphorylation affects the residues surrounding the exon E8a-coded amino acids, causing a local conformational change. We suggest that phosphorylation, without affecting demethylase activity, causes in neurons CoREST and HDAC1/2 corepressors detachment from LSD1-8a and impairs neuronal LSD1-8a repressive activity. In neurons, Thr369b phosphorylation is required for morphogenic activity, converting neuronal LSD1-8a in a dominant-negative isoform, challenging LSD1-mediated transcriptional repression on target genes. Keywords: corepressor, epigenetics, KDM1A/LSD1, neuronal maturation, transcription. Neurons acquire a proper morphology during late embryonic development and early post-natal life. Specific morphogenesis together with the possibility to remodel neurite arborization during the adult life, provide neurons with unique plasticity essential to complex cognitive functions (de la Torre-Ubieta and Bonni 2011). Transcriptional repression through epigenetic mechanisms is emerging as a key process to control developmental programs and crucial to modulate Abbreviations used: LSD1, lysine-specific demethylase 1; PTM, posttranslational modifications.

Differential Properties of Transcriptional Complexes Formed by the CoREST Family

“…Immunoprecipitates with anti-Myc antibodies obtained from 2 mg of whole HEK293 cell extracts were tested for their associated histone deacetylase activity as we described previously (31). Briefly, immunoprecipitates were incubated for 60 min with a short peptide substrate containing an acetylated lysine residue that can be deacetylated by class I, II, and IV HDAC enzymes.…”

LSD1 modulates stress-evoked transcription of immediate early genes and emotional behavior

“…In mammals, neurospecific splicing of microexon E8a generates the dominant-negative splicing isoform of LSD1 (neuroLSD1), which is required for the acquisition of proper neurite morphology inherent in neuronal maturation (11). Although conventional LSD1 acts as a constitutive repressor through its H3K4 demethylase activity, neuroLSD1 is unable to repress transcription (11,12). It has been shown recently that neuroLSD1 lacks dimethylated H3K4 (H3K4me2) demethylase activity, confirming its role as a dominant-negative LSD1 isoform (13).…”

“…The neuroLSD1-containing complex also can act as transcriptional activator by acquiring H3K9me2 and H4K20 demethylase activity (13,14). In this context, the finding that LSD1 and neuroLSD1 share a subset of target genes (12)(13)(14) suggests that modulation of exon E8a splicing may represent a mechanism for fine-tuning the transcription of selected targets. The generation of a mouse model lacking microexon E8a (neuroLSD1 KO mice) allowed us to characterize neuroLSD1 as an in vivo modulator of hippocampal excitability.…”

Sumoylation of the histone demethylase KDM4A is required for binding to tumor suppressor p53 in HCT116 colon cancer cell lines

“…Class II (JmjC domain-containing histone demethylases) are Fe (II) and 2-oxoglutaratedependent demethylases, which reverse lysine mono, di, and trimethylation (Anand and Marmorstein 2007). Recently, many studies found that the functions of HDMs are regulated by post-translational modifications (PTMs) such as methylation, phosphorylation, acetylation, ubiquitination, and sumoylation (Baba et al 2011;Cheng et al 2014;Toffolo et al 2014). KDM4A can also be controlled via post-translational modifications (Tan et al 2011).…”