Inactivation of cardiotrophin-like cytokine, a second ligand for ciliary neurotrophic factor receptor, leads to cold-induced sweating syndrome in a patient

Abstract

Ciliary neurotrophic factor (CNTF) receptor controls a pathway supporting the differentiation and survival of a wide range of neural cell types during development and in adulthood. Cardiotrophin-like cytokine (CLC)-cytokine-like factor 1 (CLF) composite cytokine is a second ligand for the CNTF ␣-component receptor (CNTFR␣). This composite cytokine is built on the structural model of IL-12, with a complex formed by a four-helix bundle type I cytokine, CLC (also referred to as CLCF1), bound to a soluble receptor subunit, CLF (also known as CRLF1). We have reported mutations in the chaperone soluble receptor CLF, causing coldinduced sweating syndrome (CISS). In this study, we studied the CLC-mutated alleles in a patient suffering from a similar disease. This patient was compound heterozygous for two different CLC mutations. The first allele was inactivated by a stop codon at position 107 (Y107X). In the second allele, a R197L mutation in the CLC-predicted binding site to the CNTFR␣ was detected. Functional analysis of the mutated protein revealed an incapacity for R197L CLC to bind to CNTFR␣ and activate the subsequent signaling events. Structural and docking interaction studies showed that the R197L substitution destabilized the contact site between CLC and CNTFR␣.gene inactivation

Ciliary Neurotrophic Factor, Cardiotrophin-like Cytokine, and Neuropoietin Share a Conserved Binding Site on the Ciliary Neurotrophic Factor Receptor α Chain

“…Strikingly, CLC Trp 94 , in agreement with our previous study (21), and NP Trp 85 contributed to a hydrophobic pocket complementary to CNTFR␣ Phe 172 (data not shown). Molecular Docking of CNTFR␣ with Its Ligands-To further characterize the interaction of CNTFR␣ with its three ligands, molecular docking experiments were carried out.…”

“…CNTFR␣ was modeled as previously reported (21). Additional refinements of the CNTFR␣ model were carried out by optimizing side chain conformation using SCRWL3 (44).…”

“…Molecular Modeling of CNTFR␣-To identify counterpart(s) of the binding site 1 of CNTF, CLC, and NP on CNTFR␣, we analyzed the CNTFR␣ model that we previously reported (21). For this purpose, we refined this model by optimizing the side chain conformation using SCRWL3.…”

“…Molecular Docking of CNTFR␣ with Its Ligands-To further characterize the interaction of CNTFR␣ with its three ligands, molecular docking experiments were carried out. The IL-6⅐IL-6R␣ complex was used as a template to build preliminary CNTF⅐CNTFR␣ and NP⅐CNTFR␣ models (the CLC⅐CNTFR␣ docking model was previously published (21)). The precise cytokine-receptor orientations were computed using HEX to optimize protein shape complementarities.…”

“…We have recently reported inactivating mutations in the CLC gene of a patient suffering from cold-induced sweating syndrome (21). This syndrome is characterized by a profuse sweating after exposure to cold.…”