RNF41 (Nrdp1) controls type 1 cytokine receptor degradation and ectodomain shedding

Abstract

Cytokines, such as interferons, erythropoietin, leptin and most interleukins, signal through type 1 cytokine receptors and activate the canonical JAK–STAT pathway. Aberrant cytokine signalling underlies numerous pathologies and adequate, temporary receptor activation is therefore under tight control. Negative-feedback mechanisms are very well studied, but cellular sensitivity also depends on the number of receptors exposed at the cell surface. This is determined by the equilibrium between receptor synthesis and transport to the plasma membrane, internalisation and recycling, degradation and ectodomain shedding, but the molecular basis of how cells establish steady state receptor levels is poorly understood. Here, we report that ring finger protein 41 (RNF41, also known as E3 ubiquitin-protein ligase Nrdp1) interacts with JAK2-associated cytokine receptor complexes and modulates their cell surface exposure and signalling. Moreover, ectopic expression of RNF41 affected turnover of leptin, leukaemia inhibitory factor and interleukin-6 receptor in a dual way: it blocked intracellular cathepsin-L-dependent receptor cleavage and concomitantly enhanced receptor shedding by metalloproteases of the ADAM family. Receptor degradation and shedding are thus interconnected phenomena with a single protein, RNF41, determining the balance.

Different Soluble Forms of the Interleukin-6 Family Signal Transducer gp130 Fine-tune the Blockade of Interleukin-6 Trans-signaling

“…Far less attention has been paid to a possible role for metalloproteases in the generation of sgp130, probably because this is generally believed to solely result from alternative mRNA splicing (2). However, recent studies showed that metalloproteases participate in the generation of soluble forms of the leukemia inhibitory factor receptor (LIFR) (22) and of the IL-27R WSX-1 (23), two other ␤ receptors that are used by IL-6 family of cytokines (24).…”

Proteome-scale Binary Interactomics in Human Cells

“…The interactome of a designated protein of interest can be determined efficiently, as such enabling "pathway walking" where serial identification of novel binding proteins supports signal transduction pathway mapping. The identification of RNF41 interaction partners is an example of such an approach: RNF41 itself was found an interaction partner of the leptin receptor complex in a MAPPIT screen (20), we here report the identification VPS52 and ASB6 as RNF41 binding proteins, and the analysis of additional MAPPIT screens to identify downstream interactors is currently ongoing (Masschaele et al, in preparation; De Ceuninck et al, in preparation). Apart from mapping the basic interactome of a protein, we showed that also dynamic aspects of the interaction pattern of a particular bait can be captured at this scale.…”

“…Also the control prey plasmid expressing unfused gp130 (13), the plasmid encoding the C-terminal HMGCR prey (19), the STAT3-dependent firefly luciferase reporter pXP2d2-rPAPI-luciferase (4), pMet7-RNF41-Etag (20), pMet7-Flag-RNF41 (21), pMet7-Flag-SV40 large T (20), pCLG-DHFR (15), pCLG-GR (22), and the p(GRE)250hu.IL6P-lucϩ GRE-luciferase reporter plasmid (22) were as described before. The pXP2d2-rPAPImKate2 reporter gene plasmid was generated by replacing the firefly luciferase sequence in pXP2d2-rPAPI-luciferase (4) with the mKate2 encoding sequence (23).…”

“…The pMet7-Flag-VPS52, pMet7-VPS52-Etag, pMet7-Flag-ASB6 and pMet7-Etag-ASB6 constructs were generated through an LR reaction (Invitrogen, Carlsbad, CA) to transfer the VPS52 or ASB6 ORF from a Gateway entry clone of the human ORFeome collection to a previously described pMet7-Flag or pMet7-Etag destination vector, respectively (21). pMet7-RNF41-Flag was generated by replacing the Etag coding sequence in pMet7-RNF41-Etag (20) by the Flag-tag sequence. The pCLG-RNF41(Cys34Ser/ His36Gln) bait expressing plasmid was generated by cloning the human RNF41 ORF into the previously described pCLG vector backbone (24) and the Cys34Ser/His36Gln double mutation was introduced using site directed mutagenesis.…”

“…Through this regulatory mechanism it has been implicated in various signaling pathways, including the EGFR and TLR signal transduction cascades (29). Our group previously established that RNF41 also controls the sorting and processing of a number of JAK2-associated cytokine receptors, including the leptin, LIF and IL-6 receptors (20,21). It does so by modulating the ubiquitination status of USP8, which in turn regulates ubiquitination and stability of the ESCRT-0 complex involved in transport of internalized cytokine receptors toward multivesicular bodies for subsequent degradation in lysosomes.…”