Mutant prominin 1 found in patients with macular degeneration disrupts photoreceptor disk morphogenesis in mice
Zhenglin Yang, … , David S. Williams, Kang Zhang
Zhenglin Yang, … , David S. Williams, Kang Zhang
Published July 24, 2008
Citation Information: J Clin Invest. 2008;118(8):2908-2916. https://doi.org/10.1172/JCI35891.
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Research Article

Mutant prominin 1 found in patients with macular degeneration disrupts photoreceptor disk morphogenesis in mice

Abstract

Familial macular degeneration is a clinically and genetically heterogeneous group of disorders characterized by progressive central vision loss. Here we show that an R373C missense mutation in the prominin 1 gene (PROM1) causes 3 forms of autosomal-dominant macular degeneration. In transgenic mice expressing R373C mutant human PROM1, both mutant and endogenous PROM1 were found throughout the layers of the photoreceptors, rather than at the base of the photoreceptor outer segments, where PROM1 is normally localized. Moreover, the outer segment disk membranes were greatly overgrown and misoriented, indicating defective disk morphogenesis. Immunoprecipitation studies showed that PROM1 interacted with protocadherin 21 (PCDH21), a photoreceptor-specific cadherin, and with actin filaments, both of which play critical roles in disk membrane morphogenesis. Collectively, our results identify what we believe to be a novel complex involved in photoreceptor disk morphogenesis and indicate a possible role for PROM1 and PCDH21 in macular degeneration.

Authors

Zhenglin Yang, Yali Chen, Concepcion Lillo, Jeremy Chien, Zhengya Yu, Michel Michaelides, Martin Klein, Kim A. Howes, Yang Li, Yuuki Kaminoh, Haoyu Chen, Chao Zhao, Yuhong Chen, Youssef Tawfik Al-Sheikh, Goutam Karan, Denis Corbeil, Pascal Escher, Shin Kamaya, Chunmei Li, Samantha Johnson, Jeanne M. Frederick, Yu Zhao, Changguan Wang, D. Joshua Cameron, Wieland B. Huttner, Daniel F. Schorderet, Frances L. Munier, Anthony T. Moore, David G. Birch, Wolfgang Baehr, David M. Hunt, David S. Williams, Kang Zhang

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Figure 4

Coimmunoprecipitation of PROM1 and PCDH21 and proteolytic cleavage of PCDH21.

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Coimmunoprecipitation of PROM1 and PCDH21 and proteolytic cleavage of PC...
(A) HEK293 cells were cotransfected with PCDH21 and either WT or mutant PROM1. Immunoprecipitation was performed with anti-PCDH21, followed by anti-PROM1 immunodetection on a Western blot. Immunolabeling of WT (lane 1) and mutant (lane 3) PROM1 in the transfected cell lysates (anti-PROM1 Western blot) served as positive controls. Also shown is immunolabeling of WT (lane 2) and mutant (lane 4) PROM1 in the PCDH21 immunoprecipitates. (B) Reciprocal immunoprecipitation with PROM1 antibody after HEK293 cells were cotransfected with PCDH21-Myc and WT (lane 2) or mutant (lane 3) PROM1. Lane 1 shows WT PCDH21-Myc–transfected cell lysate (anti-Myc Western blot) as a positive control. (C) Immunoprecipitation of retinal lysates. Lysates from WT (lane 2) and mutant (lane 3) PROM1 transgenic mice were immunoprecipitated with anti-PCDH21, followed by anti-human PROM1 detection on a Western blot. Lane 1 is a PROM1 protein positive control, showing PROM1 immunolabeling of retinal lysate. (A–C) Results of negative control experiments performed using nonspecific IgG were negative. (D) Proteolytic processing of PCDH21 in PROM1 transgenic mice. Full-length (FL) and proteolytic C-terminal (CT) PCDH21 fragments were compared among PMT3 (lane 1), C57BL/6 (lane 2), PWT31 (lane 3), and PWT20 (lane 4) mice. Total retinal protein lysate (20 μg) was probed with the PCDH21 C terminus antibody; β-actin was used as a loading control. PMT3 retinas showed substantially more full-length PCDH21 and less cleaved fragment than did PWT20, PWT31 and C57BL/6 retinas. Lanes were run on the same gel but were noncontiguous.