Structural basis for ligand reception by anaplastic lymphoma kinase

The proto-oncogene ALK encodes anaplastic lymphoma kinase, a receptor tyrosine kinase that is expressed primarily in the developing nervous system. After development, ALK activity is associated with learning and memory1 and controls energy expenditure, and inhibition of ALK can prevent diet-induced obesity2. Aberrant ALK signalling causes numerous cancers3. In particular, full-length ALK is an important driver in paediatric neuroblastoma4,5, in which it is either mutated6 or activated by ligand7. Here we report crystal structures of the extracellular glycine-rich domain (GRD) of ALK, which regulates receptor activity by binding to activating peptides8,9. Fusing the ALK GRD to its ligand enabled us to capture a dimeric receptor complex that reveals how ALK responds to its regulatory ligands. We show that repetitive glycines in the GRD form rigid helices that separate the major ligand-binding site from a distal polyglycine extension loop (PXL) that mediates ALK dimerization. The PXL of o..... READ ARTICLE

Nature DOI:10.1038/s41586-021-04141-7

Authors: Tongqing Li, Steven E. Stayrook, Yuko Tsutsui, Jianan Zhang, Yueyue Wang, Hengyi Li, Andrew Proffitt, Stefan G. Krimmer, Mansoor Ahmed, Olivia Belliveau, Ian X. Walker, Krishna C. Mudumbi, Yoshihisa Suzuki, Irit Lax, Diego Alvarado, Mark A. Lemmon, Joseph Schlessinger & Daryl E. Klein

Pre-Clinical, group2Kirk SmithNovember 24, 2021Antibody therapy, CNS cancer, Kinases, X-ray crystallography

Structural basis of cytokine-mediated activation of ALK family receptors

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

Pre-Clinical, group2Kirk SmithOctober 13, 2021cancer, metabolism, X-ray crystallography, ALK