Restoration of Proper Trafficking to the Cell Surface for Membrane Proteins Harboring Cysteine Mutations

Purdue University, United States of America
PLoS ONE (Impact Factor: 3.23). 10/2012; 7(10):e47693. DOI: 10.1371/journal.pone.0047693
Source: PubMed


A common phenotype for many genetic diseases is that the cell is unable to deliver full-length membrane proteins to the cell surface. For some forms of autism, hereditary spherocytosis and color blindness, the culprits are single point mutations to cysteine. We have studied two inheritable cysteine mutants of cyclic nucleotide-gated channels that produce achromatopsia, a common form of severe color blindness. By taking advantage of the reactivity of cysteine's sulfhydryl group, we modified these mutants with chemical reagents that attach moieties with similar chemistries to the wild-type amino acids' side chains. We show that these modifications restored proper delivery to the cell membrane. Once there, the channels exhibited normal functional properties. This strategy might provide a unique opportunity to assess the chemical nature of membrane protein traffic problems.

33 Reads
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Importance Mutations in CNGA3 are the most common cause of achromatopsia and cone-rod dystrophies.Objective To identify CNGA3 mutations in patients with cone dystrophies or Leber congenital amaurosis.Design, Setting, and Participants Clinical data and genomic DNA in 267 Chinese probands from 138 families with cone dystrophies and 129 families with Leber congenital amaurosis collected at the Zhongshan Ophthalmic Center, Guangzhou, China.Main Outcomes and Measures Variants in CNGA3 and associated phenotypes, assessed by Sanger sequencing of CNGA3, bioinformatics of variants, and segregation analysis.Results Homozygous or compound heterozygous mutations in CNGA3, including 26 novel and 13 known mutations, were identified in 46 probands from 138 families with cone dystrophies, but none were found in any of the probands from 129 families with Leber congenital amaurosis. The 46 probands with CNGA3 mutations could be further classified as likely having achromatopsia (18 probands) and cone-rod dystrophies (28 probands) based on electroretinographic recordings. Analysis of family members in 17 of 46 families demonstrated good segregation of the disease with the CNGA3 mutations.Conclusions and Relevance To our knowledge, this study is the first systemic analysis of CNGA3 in Chinese patients and expands the mutational spectrum and associated phenotypes. Our results suggest that CNGA3 mutations are a common cause of cone-rod dystrophies and achromatopsia in the Chinese population. These data indicate that CNGA3-associated cone dystrophies may be a common form of early-onset severe retinal dystrophies. Therapeutic potential such as gene therapy targeting this gene may benefit some children with early-onset severe retinal dystrophies.
    Jama Ophthalmology 06/2014; 132(9). DOI:10.1001/jamaophthalmol.2014.1032 · 3.32 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The chemical modification of proteins to provide desirable functions and/or structures broadens their possibilities for use in various applications. Usually, proteins can acquire new functions and characteristics, in addition to their original ones, via the introduction of synthetic functional moieties. Here, we adopted a more radical approach to protein modification, i.e., the replacement of a functional domain of proteins with alternative chemical compounds to build “cyborg proteins.” As a proof of concept model, we chose staphylococcal α-hemolysin (Hla), which is a well-studied, pore-forming toxin. The hemolytic activity of Hla mutants was dramatically decreased by truncation of the stem domain, which forms a β-barrel pore in the membrane. However, the impaired hemolytic activity was significantly restored by attaching a pyrenyl-maleimide unit to the cysteine residue that was introduced in the remaining stem domain. In contrast, negatively charged fluorescein-maleimide completely abolished the remaining activity of the mutants.
    Molecular BioSystems 09/2014; 10(12). DOI:10.1039/C4MB00405A · 3.21 Impact Factor

Preview (2 Sources)

33 Reads
Available from