EVIDENCE THAT HAX-1 IS AN INTERLEUKIN-1α N-TERMINAL BINDING PROTEIN

• Published in: Cytokine (Philadelphia, Pa.) Pa.), 2001-08, Vol.15 (3), p.122-137
• Main Authors: Yin, Huali, Morioka, Hideo, Towle, Christine A., Vidal, Marc, Watanabe, Takeshi, Weissbach, Lawrence
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing; Amino Acid Sequence; Animals; Blotting, Western; Cartilage, Articular - metabolism; Cell Adhesion; Chondrocytes - metabolism; DNA, Complementary - metabolism; Gene Library; Humans; Immunoblotting; Interleukin-1 - metabolism; interleukin-1α/HAX-1/intracrine signalling/yeast two-hybrid/in vitro binding; Membrane Proteins - metabolism; Molecular Sequence Data; Peptides - chemistry; Plasmids - metabolism; Precipitin Tests; Protein Binding; Protein Structure, Tertiary; Proteins - metabolism; Proteins - physiology; Recombinant Proteins - metabolism; Sequence Homology, Amino Acid; Signal Transduction; Tissue Distribution; Transfection; TRPP Cation Channels; Two-Hybrid System Techniques
• ISSN: 1043-4666; 1096-0023
• DOI: 10.1006/cyto.2001.0891

During studies aimed at understanding the function of the N-terminal peptide of interleukin-1α (IL-1 NTP, amino acids 1–112), which is liberated from the remainder of IL-1α during intracellular processing, we identified by yeast two-hybrid analysis a putative interacting protein previously designated as HAX-1. In vitro binding studies and transient transfection experiments confirmed that HAX-1 can associate with the IL-1 NTP. HAX-1 was first identified as a protein that associates with HS1, a target of non-receptor protein tyrosine kinases within haematopoietic cells. Recent data have also revealed interactions between HAX-1 and three disparate proteins, polycystin-2 (derived from the PKD2 gene), a protein linked to polycystic kidney disease, cortactin, and Epstein-Barr virus nuclear antigen leader protein (EBNA-LP). Sequence analysis of different HAX-1 binding domains revealed a putative consensus binding motif that is present in various intracellular proteins. Overlapping peptides comprising the IL-1 NTP were synthesized, and binding experiments revealed that discrete peptides were capable of interacting with HAX-1. HAX-1 may serve to retain the IL-1 NTP in the cytoplasm, and complex formation between the IL-1 NTP and HAX-1 may play a role in motility and/or adhesion of cells.