55 research outputs found
Bridging the gap: Defining the molecular mechanisms of CEP290 disease pathogenesis
No full textMutations in the gene CEP290 cause an array of debilitating and phenotypically distinct human diseases, ranging in severity from the devastating blinding disease Leber congenital amaurosis (LCA) to Senior Løken Syndrome, Joubert syndrome, and the embryonically lethal Meckel-Grüber syndrome. The pathology observed in these diseases is thought to be due to CEP290\u27s essential role in the development and maintenance of the primary cilium, but despite its critical role in biology and disease we know only little about CEP290\u27s function. Here we identify four novel functional domains of the protein, showing that CEP290 directly binds to cellular membranes through an N-terminal domain that includes a highly conserved amphipathic helix motif, and to microtubules through a domain located within its myosin-tail homology domain. Furthermore, CEP290 activity was found to be regulated by two novel autoinhibitory domains within its N- and C-termini, both of which were also found to play critical roles in regulating ciliogenesis. Disruption of the microtubule-binding domain in the rd16 mouse LCA model was found to be sufficient to induce significant deficits in cilium formation leading to retinal degeneration. Taking these findings into account, we developed a novel model that accurately predicts patient CEP290 protein levels in a mutation-specific fashion. Predicted CEP290 protein levels were found to robustly correlate with disease severity for all reported CEP290 patients. All these data implicate CEP290 as an integral structural and regulatory component of the primary cilium and provide insight into the pathological mechanisms of LCA and related ciliopathies. Our findings also suggest novel strategies for therapeutic intervention in the treatment of CEP290-based disease that, if fully realized, would be the first treatment available for the many patients suffering the devastating effects of CEP290 dysfunction
The Bionic Retina: A Small Molecule with Big Potential for Visual Restoration
No full textIn this issue of Neuron, Polosukhina et al. (2012) intravitreally deliver the light-activatable molecule acrylamide-azobenzene-quaternary ammonium (AAQ) to the eyes of mice with end-stage retinal degeneration. Results show that, with the appropriate illumination, AAQ restores light sensitivity and visual behavior
Sci Transl Med
No full textGenetic pleiotropy, the phenomenon by which mutations in the same gene result in markedly different disease phenotypes, has proven difficult to explain with traditional models of disease pathogenesis. We have developed a model of pleiotropic disease that explains, through the process of basal exon skipping, how different mutations in the same gene can differentially affect protein production, with the total amount of protein produced correlating with disease severity. Mutations in the centrosomal protein of 290 kDa (CEP290) gene are associated with a spectrum of phenotypically distinct human diseases (the ciliopathies). Molecular biologic examination of CEP290 transcript and protein expression in cells from patients carrying CEP290 mutations, measured by quantitative polymerase chain reaction and Western blotting, correlated with disease severity and corroborated our model. We show that basal exon skipping may be the mechanism underlying the disease pleiotropy caused by CEP290 mutations. Applying our model to a different disease gene, CC2D2A (coiled-coil and C2 domains-containing protein 2A), we found that the same correlations held true. Our model explains the phenotypic diversity of two different inherited ciliopathies and may establish a new model for the pathogenesis of other pleiotropic human diseases.1DP2OD007483/OD/NIH HHS/United States1F30AG044078-01A1/AG/NIA NIH HHS/United States1R24 EY019861-01A1/EY/NEI NIH HHS/United States8DP1EY023177/DP/NCCDPHP CDC HHS/United StatesDP1 EY023177/EY/NEI NIH HHS/United StatesDP1 OD008267/OD/NIH HHS/United StatesR24EY019861/EY/NEI NIH HHS/United StatesHoward Hughes Medical Institute/United States2016-06-10T00:00:00Z26062849PMC448648
Genotype-Phenotype Correlations in 208 Individuals with Coffin-Siris Syndrome
No full textCoffin-Siris syndrome (CSS, MIM 135900) is a multi-system intellectual disability syndrome characterized by classic dysmorphic features, developmental delays, and organ system anomalies. Genes in the BRG1(BRM)-associated factors (BAF, Brahma associated factor) complex have been shown to be causative, including ARID1A, ARID1B, ARID2, DPF2, SMARCA4, SMARCB1, SMARCC2, SMARCE1, SOX11, and SOX4. In order to describe more robust genotype-phenotype correlations, we collected data from 208 individuals from the CSS/BAF complex registry with pathogenic variants in seven of these genes. Data were organized into cohorts by affected gene, comparing genotype groups across a number of binary and quantitative phenotypes. We determined that, while numerous phenotypes are seen in individuals with variants in the BAF complex, hypotonia, hypertrichosis, sparse scalp hair, and hypoplasia of the distal phalanx are still some of the most common features. It has been previously proposed that individuals with ARID-related variants are thought to have more learning and developmental struggles, and individuals with SMARC-related variants, while they also have developmental delay, tend to have more severe organ-related complications. SOX-related variants also have developmental differences and organ-related complications but are most associated with neurodevelopmental differences. While these generalizations still overall hold true, we have found that all individuals with BAF-related conditions are at risk of many aspects of the phenotype, and management and surveillance should be broad
A Network of Nuclear Envelope Membrane Proteins Linking Centromeres to Microtubules
No full textSummaryIn the fission yeast S. pombe, nuclei are actively positioned at the cell center by microtubules. Here, we show that cytoplasmic microtubules are mechanically coupled to the nuclear heterochromatin through proteins embedded in the nuclear envelope. This includes an integral outer nuclear membrane protein of the KASH family (Kms2) and two integral inner nuclear membrane proteins, the SUN-domain protein Sad1 and the previously uncharacterized protein Ima1. Ima1 specifically binds to heterochromatic regions and promotes the tethering of centromeric DNA to the SUN-KASH complex. In the absence of Ima1, or in cells harboring mutations in the centromeric Ndc80 complex, inefficient coupling of centromeric heterochromatin to Sad1 leads to striking defects in the ability of the nucleus to tolerate microtubule-dependent forces, leading to changes in nuclear shape, loss of spindle pole body components from the nuclear envelope, and partial dissociation of SUN-KASH complexes. This work highlights a framework for communication between cytoplasmic microtubules and chromatin
The final demise of Rodriguez lethal acrofacial dysostosis: A case report and review of the literature
No full textInteraction between Epsin/Yap180 Adaptors and the Scaffolds Ede1/Pan1 Is Required for Endocytosis
No full textExistence of a novel clathrin-independent endocytic pathway in yeast that depends on Rho1 and formin
No full textYeast is a powerful model organism for dissecting the temporal stages and choreography of the complex protein machinery during endocytosis. The only known mechanism for endocytosis in yeast is clathrin-mediated endocytosis, even though clathrin-independent endocytic pathways have been described in other eukaryotes. Here, we provide evidence for a clathrin-independent endocytic pathway in yeast. In cells lacking the clathrin-binding adaptor proteins Ent1, Ent2, Yap1801, and Yap1802, we identify a second endocytic pathway that depends on the GTPase Rho1, the downstream formin Bni1, and the Bni1 cofactors Bud6 and Spa2. This second pathway does not require components of the better-studied endocytic pathway, including clathrin and Arp2/3 complex activators. Thus, our results reveal the existence of a second pathway for endocytosis in yeast, which suggests similarities with the RhoA-dependent endocytic pathways of mammalian cells.</jats:p
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