Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
Proteins segregate into discrete subcellular compartments via a variety of mechanisms, including motor protein transport, local binding, and diffusion barriers. This physical separation of cell functions serves, in part, as a mechanism for controlling compartment activity by allowing regulation of local protein concentrations. In this study we explored how soluble protein size impacts access to the confined space within the retinal photoreceptor outer segment signaling compartment and discovered a strikingly steep relationship. We find that GFP monomers, dimers, and trimers expressed transgenically in frog rods are present in the outer segment at 1.8-, 2.9-, and 6.8-fold lower abundances, relative to the cell body, than the small soluble fluorescent marker, calcein. Theoretical analysis, based on statistical-mechanical models of molecular access to polymer meshes, shows that these observations can be explained by the steric hindrance of molecules occupying the highly constrained spaces between outer segment disc membranes. This mechanism may answer a long-standing question of how the soluble regulatory protein, arrestin, is effectively excluded from the outer segments of dark-adapted rods and cones. Generally, our results suggest an alternate mode for the control of protein access to cell domains based on dynamic, size-dependent compartmental partitioning that does not require diffusion barriers, active transport, or large numbers of immobile binding sites.
Calvert,
Light-driven translocation of signaling proteins in vertebrate photoreceptors.
2006, Pubmed
Calvert,
Light-driven translocation of signaling proteins in vertebrate photoreceptors.
2006,
Pubmed Calvert,
Diffusion of a soluble protein, photoactivatable GFP, through a sensory cilium.
2010,
Pubmed
,
Xenbase Calvert,
Fluorescence relaxation in 3D from diffraction-limited sources of PAGFP or sinks of EGFP created by multiphoton photoconversion.
2007,
Pubmed Dishinger,
Ciliary entry of the kinesin-2 motor KIF17 is regulated by importin-beta2 and RanGTP.
2010,
Pubmed Francis,
A hierarchy of signals regulates entry of membrane proteins into the ciliary membrane domain in epithelial cells.
2011,
Pubmed Gross,
Control of rhodopsin's active lifetime by arrestin-1 expression in mammalian rods.
2010,
Pubmed Hanson,
Each rhodopsin molecule binds its own arrestin.
2007,
Pubmed Hanson,
A model for the solution structure of the rod arrestin tetramer.
2008,
Pubmed Heller,
The osmotic behavior of rod photoreceptor outer segment discs.
1971,
Pubmed Hiller,
Radioimmunoassay for tubulin: a quantitative comparison of the tubulin content of different established tissue culture cells and tissues.
1978,
Pubmed Hirsch,
The 2.8 A crystal structure of visual arrestin: a model for arrestin's regulation.
1999,
Pubmed Hu,
A septin diffusion barrier at the base of the primary cilium maintains ciliary membrane protein distribution.
2010,
Pubmed Huang,
Visual Arrestin 1 acts as a modulator for N-ethylmaleimide-sensitive factor in the photoreceptor synapse.
2010,
Pubmed Imamoto,
Concentration-dependent tetramerization of bovine visual arrestin.
2003,
Pubmed Janson,
Mechanism and size cutoff for steric exclusion from actin-rich cytoplasmic domains.
1996,
Pubmed Knox,
Transgene expression in Xenopus rods.
1998,
Pubmed
,
Xenbase Lambright,
The 2.0 A crystal structure of a heterotrimeric G protein.
1996,
Pubmed Lukov,
Role of the isoprenyl pocket of the G protein beta gamma subunit complex in the binding of phosducin and phosducin-like protein.
2004,
Pubmed Marszalek,
Genetic evidence for selective transport of opsin and arrestin by kinesin-II in mammalian photoreceptors.
2000,
Pubmed Minton,
Confinement as a determinant of macromolecular structure and reactivity.
1992,
Pubmed Nair,
Direct binding of visual arrestin to microtubules determines the differential subcellular localization of its splice variants in rod photoreceptors.
2004,
Pubmed Nickell,
Three-dimensional architecture of murine rod outer segments determined by cryoelectron tomography.
2007,
Pubmed Papadopoulos,
Extracellular space diffusion in central nervous system: anisotropic diffusion measured by elliptical surface photobleaching.
2005,
Pubmed Pedersen,
Intraflagellar transport (IFT) role in ciliary assembly, resorption and signalling.
2008,
Pubmed Peet,
Quantification of the cytoplasmic spaces of living cells with EGFP reveals arrestin-EGFP to be in disequilibrium in dark adapted rod photoreceptors.
2004,
Pubmed
,
Xenbase Peterson,
A role for cytoskeletal elements in the light-driven translocation of proteins in rod photoreceptors.
2005,
Pubmed
,
Xenbase Rosenkranz,
New aspects of the ultrastructure of frog rod outer segments.
1977,
Pubmed Smith,
Interaction of arrestin with enolase1 in photoreceptors.
2011,
Pubmed
,
Xenbase Sokolov,
Phosducin facilitates light-driven transducin translocation in rod photoreceptors. Evidence from the phosducin knockout mouse.
2004,
Pubmed Strissel,
Arrestin translocation is induced at a critical threshold of visual signaling and is superstoichiometric to bleached rhodopsin.
2006,
Pubmed Tsukamoto,
The number, depth and elongation of disc incisures in the retinal rod of Rana catesbeiana.
1987,
Pubmed Wensel,
Signal transducing membrane complexes of photoreceptor outer segments.
2008,
Pubmed Zhang,
UNC119 is required for G protein trafficking in sensory neurons.
2011,
Pubmed
