TY  - JOUR
A1  - Batra-Safferling, Renu
A1  - Abarca Heidemann, Karin
A1  - Körschen, Heinz Gerd
A1  - Tziatzios, Christos
A1  - Stoldt, Matthias
A1  - Budyak, Ivan
A1  - Willbold, Dieter
A1  - Schwalbe, Harald
A1  - Klein-Seetharaman, Judith
A1  - Kaupp, Ulrich Benjamin
T1  - Glutamic acid-rich proteins of rod photoreceptors are natively unfolded
T2  - Journal of biological chemistry
N2  - The outer segment of vertebrate photoreceptors is a specialized compartment that hosts all the signaling components required for visual transduction. Specific to rod photoreceptors is an unusual set of three glutamic acid-rich proteins (GARPs) as follows: two soluble forms, GARP1 and GARP2, and the N-terminal cytoplasmic domain (GARP′ part) of the B1 subunit of the cyclic GMP-gated channel. GARPs have been shown to interact with proteins at the rim of the disc membrane. Here we characterized native GARP1 and GARP2 purified from bovine rod photoreceptors. Amino acid sequence analysis of GARPs revealed structural features typical of “natively unfolded” proteins. By using biophysical techniques, including size-exclusion chromatography, dynamic light scattering, NMR spectroscopy, and circular dichroism, we showed that GARPs indeed exhibit a large degree of intrinsic disorder. Analytical ultracentrifugation and chemical cross-linking showed that GARPs exist in a monomer/multimer equilibrium. The results suggested that the function of GARP proteins is linked to their structural disorder. They may provide flexible spacers or linkers tethering the cyclic GMP-gated channel in the plasma membrane to peripherin at the disc rim to produce a stack of rings of these protein complexes along the long axis of the outer segment. GARP proteins could then provide the environment needed for protein interactions in the rim region of discs.
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/76243
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-762436
SN  - 0021-9258
VL  - 281
IS  - 3
SP  - 1449
EP  - 1460
PB  - American Society for Biochemistry and Molecular Biology Publications
CY  - Bethesda, Md
ER  -