Galectin-8

Galectin-8 is a secreted β-galactoside-binding lectin that modulates cell adhesion by ligating integrins and triggering focal adhesion kinase and paxillin phosphorylation^[1]. Mechanistically, Galectin-8 also monitors endosomal and lysosomal integrity by binding host glycans exposed on damaged Salmonella-containing vacuoles and recruiting NDP52 to activate antibacterial autophagy^[2]. In lysosomal damage models, Galectin-8 associates with the mTOR apparatus on lysosomes and inhibits mTOR activity through Ragulator-Rag signaling, linking membrane injury to autophagy and defense against Mycobacterium tuberculosis^[3]. In disease-relevant cartilage models, Galectin-8 correlated with cartilage degeneration, was secreted by osteoarthritic chondrocytes, and induced a pro-degradative/inflammatory NF-κB-controlled gene signature^[4]. Compared with related isoforms, this tandem-repeat Galectin-8 signature overlapped with Galectin-1 and Galectin-3 responses but also showed supplementary features, while osteoclast studies identified predominant activity of the short Galectin-8 isoform in bone resorption^[4][5]. For experimental applications, recombinant Galectin-8 has been used to induce RANKL expression, osteoclastogenesis, cytokine secretion, and cancer-cell migration, whereas thiodigalactoside or sugar-binding-defective Galectin-8 variants help separate glycan-dependent from glycan-independent mechanisms^[6][7].

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