Novel activating mutations lacking cysteine in type I cytokine receptors in acute lymphoblastic leukemia.
Gain-of-function somatic mutations introducing cysteines to either the extracellular or to the transmembrane domain (TMD) in interleukin-7 receptor α (IL7R) or cytokine receptor-like factor 2 (CRLF2) have been described in acute lymphoblastic leukemias. Here we report noncysteine in-frame mutations in IL7R and CRLF2 located in a region of the TMD closer to the cytosolic domain. Biochemical and functional assays showed that these are activating mutations conferring cytokine-independent growth of progenitor lymphoid cells in vitro and are transforming in vivo. Protein fragment complementation assays suggest that despite the absence of cysteines, the mechanism of activation is through ligand-independent dimerization. Mutagenesis experiments and ConSurf calculations suggest that the mutations stabilize the homodimeric conformation, positioning the cytosolic kinases in predefined orientation to each other, thereby inducing spontaneous receptor activation independently of external signals. Hence, type I cytokine receptors may be activated in leukemia through 2 types of transmembrane somatic dimerizing mutations.
Childhood Leukemia Research Institute, Edmond and Lily Safra Children Hospital, Sheba Medical Center, Ramat Gan, Israel; Department of Human Molecular Genetics, Migal-Galilee Bio-Technology Center, Kiryat-Shmona, Israel; Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Bio-Technology Department, Human Molecular Genetics Lab, Tel Hai Academic College, Tel Hai, Israel;
Chen
C
Shochat
Childhood Leukemia Research Institute, Edmond and Lily Safra Children Hospital, Sheba Medical Center, Ramat Gan, Israel; Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel;
Noa
N
Tal
Ludwig Institute for Cancer Research and de Duve Institute, Université Catholique de Louvain, Brussels, Belgium;
Vitalina
V
Gryshkova
Childhood Leukemia Research Institute, Edmond and Lily Safra Children Hospital, Sheba Medical Center, Ramat Gan, Israel;
Yehudit
Y
Birger
Department of Pediatric Oncology, Hematology, and Immunology, University of Heidelberg, Heidelberg, Germany; Molecular Medicine Partnership Unit, Heidelberg, Germany;
Obul R
OR
Bandapalli
Centro Ricerca Tettamanti, Clinica Pediatrica, University of Milano-Bicocca, Ospedale San Gerardo, Monza, Italy;
Giovanni
G
Cazzaniga
Childhood Leukemia Research Institute, Edmond and Lily Safra Children Hospital, Sheba Medical Center, Ramat Gan, Israel; The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel;
Nava
N
Gershman
Department of Pediatric Oncology, Hematology, and Immunology, University of Heidelberg, Heidelberg, Germany; Molecular Medicine Partnership Unit, Heidelberg, Germany;
Andreas E
AE
Kulozik
Centro Ricerca Tettamanti, Clinica Pediatrica, University of Milano-Bicocca, Ospedale San Gerardo, Monza, Italy;
Andrea
A
Biondi
Department of Pediatric Oncology, Dana-Farber Cancer Institute/Harvard Medical School, Boston, MA; Department of Haematology, Cancer Institute, University College London, London, United Kingdom;
Marc R
MR
Mansour
Laboratory of Protein Signaling and Interactions, Interdisciplinary Cluster for Applied Genoproteomics, University of Liège, Sart-Tilman, Belgium; and.
Jean-Claude
JC
Twizere
Department of Pediatric Oncology, Hematology, and Immunology, University of Heidelberg, Heidelberg, Germany; Molecular Medicine Partnership Unit, Heidelberg, Germany;
Martina U
MU
Muckenthaler
Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
Nir
N
Ben-Tal
Ludwig Institute for Cancer Research and de Duve Institute, Université Catholique de Louvain, Brussels, Belgium;
Stefan N
SN
Constantinescu
Department of Human Molecular Genetics, Migal-Galilee Bio-Technology Center, Kiryat-Shmona, Israel; Bio-Technology Department, Human Molecular Genetics Lab, Tel Hai Academic College, Tel Hai, Israel;
Dani
D
Bercovich
Childhood Leukemia Research Institute, Edmond and Lily Safra Children Hospital, Sheba Medical Center, Ramat Gan, Israel; Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel;
Shai
S
Izraeli
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002478:Cells, Cultured; D003545:Cysteine; D004252:DNA Mutational Analysis; D005260:Female; D005434:Flow Cytometry; D064593:Heterografts; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000235:genetics; D009154:Mutation; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics*; D018121:Receptors, Cytokine / Q000235:genetics*; D020395:Receptors, Interleukin-7 / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics; D014161:Transduction, Genetic
C498762:CRLF2 protein, human; D018121:Receptors, Cytokine; D020395:Receptors, Interleukin-7; D003545:Cysteine