Glutamic acid-rich proteins of rod photoreceptors are natively unfolded

Glutamic acid-rich proteins of rod photoreceptors are natively unfolded
Engineering Village 2
? 2006 Elsevier Inc
Accession number: 06219901745

Title: Glutamic acid-rich proteins of rod photoreceptors are natively unfolded

Authors: Batra-Safferling, Renu; Abarca-Heidemann, Karin; Korschen, Heinz Gerd; Tziatzios, Christos; Stoldt, Matthias; Budyak, Ivan; Willbold, Dieter; Schwalbe, Harald; Klein-Seetharaman, Judith; Kaupp, U. Benjamin

Author affiliation: Institut fur Biologische Informationsverarbeitung 1, FZJ-IBI-1, 52425 Julich, Germany

Serial title: Journal of Biological Chemistry

Abbreviated serial title: J. Biol. Chem.

Volume: v 281

Issue: n 3

Issue date: Jan 20 2006

Publication year: 2006

Pages: p 1449-1460

Language: English

ISSN: 0021-9258


Document type: Journal article (JA)

Publisher: American Society for Biochemistry and Molecular Biology Inc., Bethesda, MD 20814, United States

Abstract: 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 prime 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, NMRspectroscopy, 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. ? 2006 by The American Society for Biochemistry and Molecular Biology, Inc.

Number of references: 72

Ei main heading: Proteins

Ei controlled terms: Amino acids - Cells - Light scattering - Chromatography - Nuclear magnetic resonance - Complexation

Uncontrolled terms: Photoreceptors - Glutamic acid-rich proteins (GARP) - Disc membrane - Amino acid sequence analysis

Ei classification codes: 804.1 Organic Compounds - 461.2 Biological Materials - 741.1 Light/Optics - 801 Chemistry - 931.2 Physical Properties of Gases, Liquids & Solids - 802.2 Chemical Reactions

Treatment: Literature review (LIT); Theoretical (THR); Experimental (EXP)

DOI: 10.1074/jbc.M505012200

Database: Compendex

Compilation and indexing terms, ? 2006 Elsevier Inc. All rights reserved
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