Interleukin-6 receptor subunit alpha (IL-6Rα) (IL-6Rα)

The Interleukin-6 receptor subunit alpha (IL-6Rα) is a critical component of the IL-6 signaling complex, primarily responsible for binding the pro-inflammatory cytokine interleukin-6 with high affinity [1, 2]. It exists as both a membrane-bound protein (mIL-6R) and a soluble form (sIL-6R), the latter of which can facilitate trans-signaling in cells that do not naturally express the receptor but do express the signal-transducing subunit gp130 [3]. Upon binding IL-6, the IL-6/IL-6R complex recruits two molecules of gp130, triggering the JAK/STAT, MAPK, and PI3K signaling pathways to regulate immune responses, hematopoiesis, and the acute-phase response [1, 3]. Overexpression or overactivity of this pathway is strongly linked to the pathogenesis of autoimmune disorders like rheumatoid arthritis, systemic juvenile idiopathic arthritis, and life-threatening cytokine release syndrome [4, 5]. Consequently, IL-6Rα has become a major therapeutic target, with monoclonal antibodies such as tocilizumab and sarilumab designed to competitively inhibit IL-6 binding [4]. These therapies are effective in reducing systemic inflammation but carry risks of serious infections and gastrointestinal perforation due to the receptor's role in mucosal integrity and host defense [5]. Clinical monitoring of patients on IL-6Rα inhibitors typically involves tracking C-reactive protein levels and absolute neutrophil counts to ensure safety and efficacy [4, 5]. References: [1] UniProt (P08887); [2] NCBI Gene (3570); [3] PubMed (PMID: 30204754); [4] FDA Label (Actemra); [5] StatPearls (IL-6 Inhibitors).

Other names

CD126IL6RAIL-6R-1Interleukin-6 receptor alpha chainIL-6R-alpha

Competitive inhibition of IL-6 binding to both membrane-bound and soluble IL-6 receptors, preventing the formation of the hexameric signaling complex with gp130 and subsequent JAK/STAT activation [3, 4].