Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Maf-family leucine zipper transcription factor NRL is essential for rod photoreceptor development and functional maintenance in the mammalian retina. Mutations in NRL are associated with human retinopathies, and loss of Nrl in mice leads to a cone-only retina with the complete absence of rods. Among the highly down-regulated genes in the Nrl(-/-) retina, we identified receptor expression enhancing protein 6 (Reep6), which encodes a member of a family of proteins involved in shaping of membrane tubules and transport of G-protein coupled receptors. Here, we demonstrate the expression of a novel Reep6 isoform (termed Reep6.1) in the retina by exon-specific Taqman assay and rapid analysis of complementary deoxyribonucleic acid (cDNA) ends (5'-RACE). The REEP6.1 protein includes 27 additional amino acids encoded by exon 5 and is specifically expressed in rod photoreceptors of developing and mature retina. Chromatin immunoprecipitation assay identified NRL binding within the Reep6 intron 1. Reporter assays in cultured cells and transfections in retinal explants mapped an intronic enhancer sequence that mediated NRL-directed Reep6.1 expression. We also demonstrate that knockdown of Reep6 in mouse and zebrafish resulted in death of retinal cells. Our studies implicate REEP6.1 as a key functional target of NRL-centered transcriptional regulatory network in rod photoreceptors.
Hum Mol Genet 2014 Aug 15
PMID:Regulation of a novel isoform of Receptor Expression Enhancing Protein REEP6 in rod photoreceptors by bZIP transcription factor NRL. 2469 51

In retinal photoreceptors, vectorial transport of cargo is critical for transduction of visual signals, and defects in intracellular trafficking can lead to photoreceptor degeneration and vision impairment. Molecular signatures associated with routing of transport vesicles in photoreceptors are poorly understood. We previously reported the identification of a novel rod photoreceptor specific isoform of Receptor Expression Enhancing Protein (REEP) 6, which belongs to a family of proteins involved in intracellular transport of receptors to the plasma membrane. Here we show that loss of REEP6 in mice (Reep6-/-) results in progressive retinal degeneration. Rod photoreceptor dysfunction is observed in Reep6-/- mice as early as one month of age and associated with aberrant accumulation of vacuole-like structures at the apical inner segment and reduction in selected rod phototransduction proteins. We demonstrate that REEP6 is detected in a subset of Clathrin-coated vesicles and interacts with the t-SNARE, Syntaxin3. In concordance with the rod degeneration phenotype in Reep6-/- mice, whole exome sequencing identified homozygous REEP6-E75K mutation in two retinitis pigmentosa families of different ethnicities. Our studies suggest a critical function of REEP6 in trafficking of cargo via a subset of Clathrin-coated vesicles to selected membrane sites in retinal rod photoreceptors.
Hum Mol Genet 2017 06 15
PMID:REEP6 mediates trafficking of a subset of Clathrin-coated vesicles and is critical for rod photoreceptor function and survival. 2836 66

Retinitis pigmentosa (RP) is the most common form of inherited retinal dystrophy. We recently identified mutations in REEP6, which encodes the receptor expression enhancing protein 6, in several families with autosomal recessive RP. REEP6 is related to the REEP and Yop1p family of ER shaping proteins and potential receptor accessory proteins, but the role of REEP6 in the retina is unknown. Here we characterize the disease mechanisms associated with loss of REEP6 function using a Reep6 knockout mouse generated by CRISPR/Cas9 gene editing. In control mice REEP6 was localized to the inner segment and outer plexiform layer of rod photoreceptors. The Reep6-/- mice exhibited progressive photoreceptor degeneration from P20 onwards. Ultrastructural analyses at P20 by transmission electron microscopy and 3View serial block face scanning EM revealed an expansion of the distal ER in the Reep6-/- rods and an increase in their number of mitochondria. Electroretinograms revealed photoreceptor dysfunction preceded degeneration, suggesting potential defects in phototransduction. There was no effect on the traffic of rhodopsin, Rom1 or peripherin/rds; however, the retinal guanylate cyclases GC1 and GC2 were severely affected in the Reep6 knockout animals, with almost undetectable expression. These changes correlated with an increase in C/EBP homologous protein (CHOP) expression and the activation of caspase 12, suggesting that ER stress contributes to cell death. Collectively, these data suggest that REEP6 plays an essential role in maintaining cGMP homeostasis though facilitating the stability and/or trafficking of guanylate cyclases and maintaining ER and mitochondrial homeostasis.
Hum Mol Genet 2017 07 15
PMID:REEP6 deficiency leads to retinal degeneration through disruption of ER homeostasis and protein trafficking. 2847 15

In the mammalian retina, rod and cone photoreceptors transmit the visual information to bipolar neurons through highly specialized ribbon synapses. We have limited understanding of regulatory pathways that guide morphogenesis and organization of photoreceptor presynaptic architecture in the developing retina. While neural retina leucine zipper (NRL) transcription factor determines rod cell fate and function, cone-rod homeobox (CRX) controls the expression of both rod- and cone-specific genes and is critical for terminal differentiation of photoreceptors. A comprehensive immunohistochemical evaluation of Crx-/- (null), CrxRip/+ and CrxRip/Rip (models of dominant congenital blindness) mouse retinas revealed abnormal photoreceptor synapses, with atypical ribbon shape, number and length. Integrated analysis of retinal transcriptomes of Crx-mutants with CRX- and NRL-ChIP-Seq data identified a subset of differentially expressed CRX target genes that encode presynaptic proteins associated with the cytomatrix active zone (CAZ) and synaptic vesicles. Immunohistochemistry of Crx-mutant retina validated aberrant expression of REEP6, PSD95, MPP4, UNC119, UNC13, RGS7 and RGS11, with some reduction in Ribeye and no significant change in immunostaining of RIMS1, RIMS2, Bassoon and Pikachurin. Our studies demonstrate that CRX controls the establishment of CAZ and anchoring of ribbons, but not the formation of ribbon itself, in photoreceptor presynaptic terminals.
Hum Mol Genet 2018 10 15
PMID:Cone-rod homeobox CRX controls presynaptic active zone formation in photoreceptors of mammalian retina. 3008 54