title: PIASx is a MEF2 SUMO E3 ligase that promotes postsynaptic dendritic morphogenesis.
abstract: Postsynaptic morphogenesis of dendrites is essential for the establishment of neural connectivity in the brain, but the mechanisms that govern postsynaptic dendritic differentiation remain poorly understood. Sumoylation of the transcription factor myocyte enhancer factor 2A (MEF2A) promotes the differentiation of postsynaptic granule neuron dendritic claws in the cerebellar cortex. Here, we identify the protein PIASx as a MEF2 SUMO E3 ligase that represses MEF2-dependent transcription in neurons. Gain-of-function and genetic knockdown experiments in rat cerebellar slices and in the postnatal cerebellum in vivo reveal that PIASx drives the differentiation of granule neuron dendritic claws in the cerebellar cortex. MEF2A knockdown suppresses PIASx-induced dendritic claw differentiation, and expression of sumoylated MEF2A reverses PIASx knockdown-induced loss of dendritic claws. These findings define the PIASx-MEF2 sumoylation signaling link as a key mechanism that orchestrates postsynaptic dendritic claw morphogenesis in the cerebellar cortex and suggest novel functions for SUMO E3 ligases in brain development and plasticity.
authors.affiliation: Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Aryaman
authors.initials: A
authors.lastname: Shalizi
authors.forename: Parizad M
authors.initials: PM
authors.lastname: Bilimoria
authors.forename: Judith
authors.initials: J
authors.lastname: Stegmüller
authors.forename: Brice
authors.initials: B
authors.lastname: Gaudillière
authors.forename: Yue
authors.initials: Y
authors.lastname: Yang
authors.forename: Ke
authors.initials: K
authors.lastname: Shuai
authors.forename: Azad
authors.initials: A
authors.lastname: Bonni
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D002478:Cells, Cultured; D002531:Cerebellum / Q000201:enzymology / Q000254:growth & development; D003712:Dendrites / Q000201:enzymology* / Q000502:physiology; D006801:Humans; D026161:MADS Domain Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D064326:MEF2 Transcription Factors; D009024:Morphogenesis / Q000235:genetics / Q000502:physiology*; D018006:Myogenic Regulatory Factors / Q000235:genetics / Q000502:physiology*; D050828:Protein Inhibitors of Activated STAT / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism / Q000502:physiology*; D013569:Synapses / Q000201:enzymology; D044767:Ubiquitin-Protein Ligases / Q000172:deficiency / Q000235:genetics / Q000502:physiology*
chemical_list: D026161:MADS Domain Proteins; D064326:MEF2 Transcription Factors; C578035:MEF2A protein, human; D018006:Myogenic Regulatory Factors; D050828:Protein Inhibitors of Activated STAT; D025841:Small Ubiquitin-Related Modifier Proteins; D044767:Ubiquitin-Protein Ligases; C484534:Pias2 protein, rat