Anaplastic lymphoma kinase (ALK)1 and the related leukocyte tyrosine kinase (LTK)2 are recently deorphanized receptor tyrosine kinases3. Together with their activating cytokines, ALKAL1 and ALKAL24,5,6 (also called FAM150A and FAM150B or AUGβ and AUGα, respectively), they are involved in neural development7, cancer7,8,9 and autoimmune diseases10. Furthermore, mammalian ALK recently emerged as a key regulator of energy expenditure and weight gain11, consistent with a metabolic role for Drosophila ALK12. Despite such functional pleiotropy and growing therapeutic relevance13,14, structural insights into ALK and LTK and their complexes with cognate cytokines have remained scarce. Here we show that the cytokine-binding segments of human ALK and LTK comprise a novel architectural chimera of a permuted TNF-like module that braces a glycine-rich subdomain featuring a hexagonal lattice of long polyglycine type II helices. The cognate cytokines ALKAL1 and ALKAL2 are monomeric three-helix bundles..... READ ARTICLE
Nature DOI:10.1038/s41586-021-03959-5
Authors: Steven De Munck, Mathias Provost, Michiko Kurikawa, Ikuko Omori, Junko Mukohyama, Jan Felix, Yehudi Bloch, Omar Abdel-Wahab, J. Fernando Bazan, Akihide Yoshimi & Savvas N. Savvides