The Cyclophilin-like Domain Mediates the Association of Ran-Binding Protein 2 with Subunits of the 19 S Regulatory Complex of the Proteasome

Paulo A Ferreira,Cai Yunfei,Diana Schick,Ronald Roepman

doi:10.1074/jbc.273.38.24676

Paulo A Ferreira, Cai Yunfei + Show 2 more

Open Access

https://doi.org/10.1074/jbc.273.38.24676

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Abstract

The combination of the Ran-binding domain 4 and cyclophilin domains of Ran-binding protein 2 selectively associate with a subset of G protein-coupled receptors, red/green opsins, upon cis-trans prolyl isomerase-dependent and direct modification of opsin followed by association of the modified opsin isoform to Ran-binding domain 4. This effect enhances in vivo the production of functional receptor and generates an opsin isoform with no propensity to self-aggregate in vitro. We now show that another domain of Ran-binding protein 2, cyclophilin-like domain, specifically associates with the 112-kDa subunit, P112, and other subunits of the 19 S regulatory complex of the 26 S proteasome in the neuroretina. This association possibly mediates Ran-binding protein 2 limited proteolysis into a smaller and stable isoform. Also, the interaction of Ran-binding protein 2 with P112 regulatory subunit of the 26 S proteasome involves still another protein, a putative kinesin-like protein. Our results indicate that Ran-binding protein 2 is a key component of a macro-assembly complex selectively linking protein biogenesis with the proteasome pathway and, thus, with potential implications for the presentation of misfolded and ubiquitin-like modified proteins to this proteolytic machinery.

Highlights

The light receptors, opsins, constitute a class of homologous receptors that are key players in the activation of the phototransduction cascade across species [7,8,9,10]
We have identified in bovine retina a cyclophilin-related protein made up of multiple and well defined structural modules [18] that is the counterpart protein of the human and murine RanBP2 reported by the Nishimoto [19], Coutavas [20], and Dabauvalle [21] groups
We have shown that the C-terminal supradomain of RanBP2, Ran-binding domain 4 (RBD4)1 and cyclophilin (CY), mediate the selective association of RanBP2 with a subclass of opsins, red/green opsins [22]

Summary

Introduction

The light receptors, opsins, constitute a class of homologous receptors that are key players in the activation of the phototransduction cascade across species [7,8,9,10]. P99 purification procedure was carried out exactly the same way with the exception that incubation assays were scaled-up ϳ360-fold, and 20% (v/v) of concentrated eluted protein was loaded on SDS-PAGE for silver-stain analysis.

Results

Conclusion