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Mutant Dominant-negative Causes Protein Aggregates Degraded Via ERAD and Prevents Normal Rhodopsin from Proper Membrane Trafficking

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Specialty Biology
Date 2024 Jun 3
PMID 38828393
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Abstract

Dominant mutations in the rhodopsin gene () contribute to 25% of autosomal dominant retinitis pigmentosa (adRP), characterized by photoreceptor loss and progressive blindness. One such mutation, carries a 3-bp deletion, resulting in the loss of one of two isoleucines at codons 255 and 256. Our investigation, using recombinant expression in HEK293 and COS-7 cells, revealed that , akin to the known adRP mutation , induces the formation of rhodopsin protein (RHO) aggregates at the perinuclear region. Co-expression of or with wild-type , mimicking the heterozygous genotype of adRP patients, demonstrated the dominant-negative effect, as all isoforms were retained in perinuclear aggregates, impeding membrane trafficking. In retinal explants from WT mice, mislocalization of labeled adRP isoforms at the outer nuclear layer was observed. Further analysis revealed that RHO aggregates are retained at the endoplasmic reticulum (ER), undergo ER-associated degradation (ERAD), and colocalize with the AAA-ATPase escort chaperone valosin-containing protein (VCP). These aggregates are polyubiquitinated and partially colocalized with the 20S proteasome subunit beta-5 (PSMB5). Pharmacological inhibition of proteasome- or VCP activity increased RHO aggregate size. In summary, RHO exhibits dominant pathogenicity by sequestering normal RHO in ER aggregates, preventing its membrane trafficking and following the ERAD degradation.

References
1.
Sung C, Davenport C, Nathans J . Rhodopsin mutations responsible for autosomal dominant retinitis pigmentosa. Clustering of functional classes along the polypeptide chain. J Biol Chem. 1993; 268(35):26645-9. View

2.
Athanasiou D, Aguila M, Bellingham J, Li W, McCulley C, Reeves P . The molecular and cellular basis of rhodopsin retinitis pigmentosa reveals potential strategies for therapy. Prog Retin Eye Res. 2017; 62:1-23. PMC: 5779616. DOI: 10.1016/j.preteyeres.2017.10.002. View

3.
Whorton M, Jastrzebska B, Park P, Fotiadis D, Engel A, Palczewski K . Efficient coupling of transducin to monomeric rhodopsin in a phospholipid bilayer. J Biol Chem. 2007; 283(7):4387-94. PMC: 2651572. DOI: 10.1074/jbc.M703346200. View

4.
Sakai T, Calderone J, Lewis G, Linberg K, Fisher S, Jacobs G . Cone photoreceptor recovery after experimental detachment and reattachment: an immunocytochemical, morphological, and electrophysiological study. Invest Ophthalmol Vis Sci. 2002; 44(1):416-25. DOI: 10.1167/iovs.02-0633. View

5.
HARGRAVE P . Rhodopsin structure, function, and topography the Friedenwald lecture. Invest Ophthalmol Vis Sci. 2001; 42(1):3-9. View