title: Targeted mutations of the juxtamembrane tyrosines in the Kit receptor tyrosine kinase selectively affect multiple cell lineages.
abstract: Loss-of-function mutations in the murine dominant white spotting/c-kit locus affect a diverse array of biological processes and cell lineages and cause a range of phenotypes, including severe anemia, defective pigmentation, sterility, mast cell deficits, a lack of interstitial cells of Cajal, spatial learning memory deficits, and defects in peripheral nerve regeneration. Here we show that tyrosine residues 567 and 569 in the juxtamembrane (Jx) domain of the murine Kit receptor tyrosine kinase are crucial for the function of Kit in melanogenesis and mast cell development, but are dispensable for the normal development of erythroid, interstitial cells of Cajal and germ cells. Furthermore, adult mice lacking both tyrosines exhibit splenomegaly, dysregulation of B-cell and megakaryocyte development, and enlarged stomachs. Analysis of signal transduction events induced by the mutant receptors after ligand stimulation indicates that Jx tyrosine mutations diminish receptor autophosphorylation and selectively attenuate activation of extracellular signal-regulated kinase/mitogen-activated protein kinases. Together, these observations demonstrate that the Jx domain of Kit plays a cell-type specific regulatory role in vivo and illustrate how engineered mutations in Kit can be used to understand the complex biological and molecular events that result from activating a receptor tyrosine kinase.
authors.affiliation: Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON, Canada M5G 1X5.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kimura
authors.forename: Nina
authors.initials: N
authors.lastname: Jones
authors.forename: Michael
authors.initials: M
authors.lastname: Klüppel
authors.forename: Masanori
authors.initials: M
authors.lastname: Hirashima
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Tachibana
authors.forename: Jason B
authors.initials: JB
authors.lastname: Cohn
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Wrana
authors.forename: Tony
authors.initials: T
authors.lastname: Pawson
authors.forename: Alan
authors.initials: A
authors.lastname: Bernstein
mesh_terms: D000818:Animals; D019070:Cell Lineage; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D051379:Mice; D016297:Mutagenesis, Site-Directed; D019009:Proto-Oncogene Proteins c-kit / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014443:Tyrosine / Q000235:genetics*
chemical_list: D014443:Tyrosine; D019009:Proto-Oncogene Proteins c-kit