title: Lipid rafts identified as locations of ectodomain shedding mediated by Meltrin beta/ADAM19.
abstract: Meltrin beta (Mel beta, also called ADAM19) is a member of the ADAM (adisintegrin and metalloprotease) family, which are membrane-anchored glycoproteins that play crucial roles in various biological processes. Many intercellular signaling molecules are membrane-anchored proteins, which are proteolytically processed after becoming membrane-bound, to liberate their extracellular domains (ectodomain shedding). Genetic and biochemical studies have shown that some ADAMs participate in these events. We found previously that Mel beta can cleave the extracellular region of the membrane-anchored beta-exon-containing Neuregulin-1 (NRG beta1) protein, which is one of the main ligands for the neural ErbB receptor. Mel beta-deficient mice showed developmental defects in the nervous system. These observations raise the possibility that the NRG ectodomain shedding mediated by Mel beta is closely related to the neural development. Here we show that Mel beta-mediated ectodomain shedding of NRG beta1 takes place in the lipid rafts of neurons. The lipid rafts localization of Mel beta requires its membrane-anchoring region, and NRG beta1 ectodomain shedding is not enhanced if Mel beta cannot reach the lipid rafts. These results indicate that localization of Mel beta in lipid rafts is critical for its ectodomain shedding.
authors.affiliation: Department of Growth Regulation, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Wakatsuki
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kurisaki
authors.forename: Atsuko
authors.initials: A
authors.lastname: Sehara-Fujisawa
mesh_terms: D051722:ADAM Proteins; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D019483:Disintegrins / Q000235:genetics / Q000378:metabolism*; D015151:Immunoblotting; D021962:Membrane Microdomains / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D045726:Metalloproteases / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D016297:Mutagenesis, Site-Directed; D020890:Neuregulin-1 / Q000235:genetics / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000235:genetics / Q000502:physiology
chemical_list: D019483:Disintegrins; D008565:Membrane Proteins; D020890:Neuregulin-1; C117467:neuregulin beta; D045726:Metalloproteases; D051722:ADAM Proteins; C096116:Adam19 protein, mouse