Purchase this article with an account.
Y. Kanan, D. M. Sherry, S. J. Fliesler, M. E. Burns, K. L. Moore, M. R. Al-Ubaidi; Lack of Protein-Tyrosine Sulfation Disrupts Retinal Function and Rod Outer Segment Structure. Invest. Ophthalmol. Vis. Sci. 2010;51(13):3488. doi: https://doi.org/.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To evaluate the importance of protein tyrosine-O-sulfation to photoreceptor structure and function.
Western analysis was used to determine the presence of sulfated proteins. Immunohistochemistry (IHC) was used to determine cellular localization of sulfated proteins. Transcript levels for both tyrosylprotein sulfotransferase genes (Tpst1 and Tpst2) were assessed by real time-PCR. Functional competence was evaluated by electroretinography (ERG). Suction electrode experiments were used to determine the functional competence of single rods. Photoreceptor structure was examined by light and electron microscopy.
Western and IHC analyses showed that multiple retinal proteins are sulfated and that sulfated proteins are present in all retinal layers. Wild type mouse retina expresses both Tpst transcripts and the steady state levels of both transcripts is developmentally regulated, with highest levels during early postnatal life and lowest by postnatal day 300. Tpst1-/- and Tpst2-/- retinasshowed normal histology, but reduced scotopic and photopic ERG responses. Double knockout (DKO; Tpst1-/-/Tpst2-/-) mice showed drastically reduced scotopic and photopic responses. However, suction electrode recordings of rods from DKO mice generated flash responses that were nearly normal with maximal response amplitudes that were slightly smaller than control values. Photoreceptor ultrastructure in DKO retina was abnormal, with large intradiscal spaces and outer segment membranous projections into the space surrounding the rods.
These results demonstrate that protein tyrosine sulfation is essential for proper rod photoreceptor structure and function.
This PDF is available to Subscribers Only