Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hirschsprung disease (HSCR) is sometimes associated with a set of characteristics including mental retardation, microcephaly, and distinct facial features, but the gene mutated in this condition has not yet been identified. Here we report that mutations in SIP1, encoding Smad interacting protein-1, cause disease in a series of cases. SIP1 is located in the deleted segment at 2q22 from a patient with a de novo t(2;13)(q22;q22) translocation. SIP1 seems to have crucial roles in normal embryonic neural and neural crest development.
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PMID:Mutations in SIP1, encoding Smad interacting protein-1, cause a form of Hirschsprung disease. 1127 15

Recently, mutations in ZFHX1B, the gene that encodes Smad-interacting protein-1 (SIP1), were found to be implicated in the etiology of a dominant form of Hirschsprung disease-mental retardation syndrome in humans. To clarify the molecular mechanisms underlying the clinical features of SIP1 deficiency, we generated mice that bear a mutation comparable to those found in several human patients. Here, we show that Zfhx1b-knockout mice do not develop postotic vagal neural crest cells, the precursors of the enteric nervous system that is affected in patients with Hirschsprung disease, and they display a delamination arrest of cranial neural crest cells, which form the skeletomuscular elements of the vertebrate head. This suggests that Sip1 is essential for the development of vagal neural crest precursors and the migratory behavior of cranial neural crest in the mouse. Furthermore, we show that Sip1 is involved in the specification of neuroepithelium.
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PMID:Mice lacking ZFHX1B, the gene that codes for Smad-interacting protein-1, reveal a role for multiple neural crest cell defects in the etiology of Hirschsprung disease-mental retardation syndrome. 1252 67

Dendritic spines in the central nervous system undergo rapid actin-based shape changes, making actin regulators potential modulators of spine morphology and synapse formation. Although several potential regulators and effectors for actin organization have been identified, the mechanisms by which these molecules assemble and localize are not understood. Here we show that the G protein-coupled receptor kinase-interacting protein (GIT)1 serves such a function by targeting actin regulators and locally modulating Rac activity at synapses. In cultured hippocampal neurons, GIT1 is enriched in both pre- and postsynaptic terminals and targeted to these sites by a novel domain. Disruption of the synaptic localization of GIT1 by a dominant-negative mutant results in numerous dendritic protrusions and a significant decrease in the number of synapses and normal mushroom-shaped spines. The phenotype results from mislocalized GIT1 and its binding partner PIX, an exchange factor for Rac. In addition, constitutively active Rac shows a phenotype similar to the GIT1 mutant, whereas dominant-negative Rac inhibits the dendritic protrusion formation induced by mislocalized GIT1. These results demonstrate a novel function for GIT1 as a key regulator of spine morphology and synapse formation and point to a potential mechanism by which mutations in Rho family signaling leads to decreased neuronal connectivity and cognitive defects in nonsyndromic mental retardation.
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PMID:Synapse formation is regulated by the signaling adaptor GIT1. 1269 2

Mutations in either the Rho GTPase pathway or in the fragile X mental retardation (FMR1) gene produce neuronal connectivity defects. In this issue of Neuron, Schenck et al. use biochemical and genetic approaches in Drosophila to examine the interactions between dFMR1 and dRac1 and provide evidence that the cytoplasmic FMRP interacting protein (CYFIP) links Rac-dependent cytoskeleton remodeling and dFMR1-dependent control of translation in a unique pathway to modulate neuronal morphogenesis.
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PMID:From fragile X mental retardation protein to Rac1 GTPase: new insights from Fly CYFIP. 1281 75

We report a girl who had Hirschsprung disease in association with distinct facial appearance, microcephaly, agenesis of the corpus callosum and mental retardation (Mowat-Wilson syndrome). Mutation analysis of the zinc finger homeo box 1 B (ZFHX1 B) gene revealed a de novo 7 bp deletion (TGGCCCC) at nucleotide 1773 (1773 delTGGCCCC) resulting in a frameshift and leading to a termination codon at amino acid residue 604 (604 X) in exon 8 C. The zinc finger homeo box 1 B (Smad interacting protein-1) is a transcription corepressor of Smad target genes with functions in the patterning of neural crest derived cells, CNS, and midline structures. Mutations in ZFHX1 B can lead to neurological disorders in addition to dysmorphic features, megacolon, and other malformations.
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PMID:Frameshift mutation of the zinc finger homeo box 1 B gene in syndromic corpus callosum agenesis (Mowat-Wilson syndrome). 1468 59

Dyrk1A, a mammalian homolog of the Drosophila minibrain gene, encodes a dual-specificity kinase, involved in neuronal development and in adult brain physiology. In humans, a third copy of DYRK1A is present in Down syndrome (trisomy 21) and has been implicated in the etiology of mental retardation. To further understand this pathology, we searched for Dyrk1A-interacting proteins and identified Arip4 (androgen receptor-interacting protein 4), a SNF2-like steroid hormone receptor cofactor. Mouse hippocampal and cerebellar neurons coexpress Dyrk1A and Arip4. In HEK293 cells and hippocampal neurons, both proteins are colocalized in a speckle-like nuclear subcompartment. The functional interaction of Dyrk1A with Arip4 was analyzed in a series of transactivation assays. Either Dyrk1A or Arip4 alone displays an activating effect on androgen receptor- and glucocorticoid receptor-mediated transactivation, and Dyrk1A and Arip4 together act synergistically. These effects are independent of the kinase activity of Dyrk1A. Inhibition of endogenous Dyrk1A and Arip4 expression by RNA interference showed that both proteins are necessary for the efficient activation of androgen receptor- and glucocorticoid receptor-dependent transcription. As Dyrk1A is an activator of steroid hormone-regulated transcription, the overexpression of DYRK1A in persons with Down syndrome may cause rather broad changes in the homeostasis of steroid hormone-controlled cellular events.
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PMID:Dyrk1A potentiates steroid hormone-induced transcription via the chromatin remodeling factor Arip4. 1519 38

Dual-specificity tyrosine(Y) regulated kinase 1A (DYRK1A) is a serine/threonine protein kinase implicated in mental retardation resulting from Down syndrome. In this study, we carried out yeast two-hybrid screening to find proteins regulating DYRK1A kinase activity. We identified 14-3-3 as a Dyrk1A interacting protein, which is consistent with the previous finding of the interaction between the yeast orthologues Yak1p and Bmh1/2p. We showed the interaction between Dyrk1A and 14-3-3 in vitro and in vivo. The binding required the N-terminus of Dyrk1A and was independent of the Dyrk1A phosphorylation status. Functionally, 14-3-3 binding increased Dyrk1A kinase activity in a dose dependent manner in vitro. In vivo, a small peptide inhibiting 14-3-3 binding, sc138, decreased Dyrk1A kinase activity in COS7. In summary, these results suggest that DYRK1A kinase activity could be regulated by the interaction of 14-3-3.
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PMID:Regulation of Dyrk1A kinase activity by 14-3-3. 1536 79

The death domain-associated protein (Daxx) was originally cloned as a CD95 (FAS)-interacting protein and modulator of FAS-induced cell death. Daxx accumulates in both the nucleus and the cytoplasm; in the nucleus, Daxx is found associated with the promyelocytic leukaemia (PML) nuclear body and with alpha-thalassemia/mental retardation syndrome protein (ATRX)-positive heterochromatic regions. In the cytoplasm, Daxx has been reported to interact with various proteins involved in cell death regulation. Despite a significant number of studies attempting to determine Daxx function in apoptotic and non-apoptotic cell death, its precise role in this process is only partially understood. Here, we critically review the current understanding of Daxx function and shed new light on this interesting field.
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PMID:Daxx: death or survival protein? 1640 23

Mowat-Wilson syndrome (MWS) is a recently delineated mental retardation (MR)-multiple congenital anomaly syndrome, characterized by typical facies, severe MR, epilepsy, and variable congenital malformations, including Hirschsprung disease (HSCR), genital anomalies, congenital heart disease (CHD), and agenesis of the corpus callosum (ACC). It is caused by de novo heterozygous mutations or deletions of the ZFHX1B gene located at 2q22. ZFHX1B encodes Smad-interacting protein-1 (SMADIP1 or SIP1), a transcriptional corepressor involved in the transforming growth factor-beta signaling pathway. It is a highly evolutionarily conserved gene, widely expressed in embryological development. Over 100 mutations have been described in patients with clinically typical MWS, who almost always have whole gene deletions or truncating mutations (nonsense or frameshift) of ZFHX1B, suggesting that haploinsufficiency is the basis of MWS pathology. No obvious genotype-phenotype correlation could be identified so far, but atypical phenotypes have been reported with missense or splice mutations in the ZFHX1B gene. In this work we describe 40 novel mutations and we summarize the various mutational reports published since the identification of the causative gene.
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PMID:ZFHX1B mutations in patients with Mowat-Wilson syndrome. 1720 59

The Aristaless-related homeobox gene (ARX) is one of the major genes causing X-linked mental retardation. We have been interested in the pathogenic mechanism of expanded polyalanine tract mutations in ARX. We showed that the c.304ins(GCG)7 mutation causing an increase from 16 to 23 alanines increased the propensity of ARX protein aggregation and a shift from nuclear to cytoplasmic localization. We proposed that mislocalization of ARX via cytoplasmic aggregation and subsequent degradation leads to a partial loss of function, contributing to the pathogenesis. We identified importin 13 (IPO13), a mediator of nuclear import for a variety of proteins, as a novel ARX interacting protein. We predicted that the transport of ARX by IPO13 from the cytoplasm to the nucleus might be disrupted by expanded polyalanine tract mutations, but our data showed that in both yeast and mammalian cells these mutant ARX proteins were still able to interact with IPO13. We established the nuclear localization regions of the ARX homeodomain that were required for the interaction with IPO13 and correct localization of the full-length ARX transcription factor to the nucleus.
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PMID:Molecular pathology of expanded polyalanine tract mutations in the Aristaless-related homeobox gene. 1749 Aug 53


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