title: A secreted type of beta1,6 N-acetylglucosaminyltransferase V (GnT-V), a novel angiogenesis inducer, is regulated by gamma-secretase.
abstract: Glycosyltransferases are present in the Golgi apparatus in a membrane-bound form and are released from cells after cleavage by certain proteases. Beta1,6-N-acetylglucosaminyltransferase V (GnT-V), which is cleaved and secreted from the cells, is involved in the biosynthesis of beta1-6GlcNAc branching on N-glycans and has been implicated in tumor progression and metastasis. We recently reported that a secreted type of GnT-V (soluble GnT-V) itself could promote angiogenesis, which is completely different from its original function as a glycosyltransferase, and this might play a role in tumor invasion. In this study, to explore the molecular basis for this functional glycosyltransferase secretion, its cleavage site was examined and the protease(s) involved in that cleavage were identified. The NH2-terminal protein sequence of purified soluble GnT-V (approximately 100 kDa) from GnT-V-overexpressed cells revealed that its terminus started at His31, located at the boundary position between the transmembrane and stem regions. This secretion was not inhibited by a single amino acid mutation at the cleavage site (Leu29, Leu30 to Asp, His31 to Ala), but specifically inhibited by addition of DFK-167, a gamma-secretase inhibitor, suggesting that gamma-secretase is a plausible protease for secretion processing. In addition, transfection of the gene of familial Alzheimer's disease (FAD)[corrected]-linked presenilin-1, a component of gamma-secretase, increased the secretion rate of endogenous GnT-V; the secretion of soluble GnT-V (approximately 100 kDa) was completely inhibited in presenilin-1/2 double-deficient cells, which have no gamma-secretase activity. Collectively, these results demonstrate that Golgi-resident GnT-V is cleaved at the transmembrane region by gamma-secretase, and this might control tumor angiogenesis through a novel pathway.
authors.affiliation: Department of Biochemistry, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Nakahara
authors.forename: Takashi
authors.initials: T
authors.lastname: Saito
authors.forename: Nami
authors.initials: N
authors.lastname: Kondo
authors.forename: Kenta
authors.initials: K
authors.lastname: Moriwaki
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Noda
authors.forename: Shinji
authors.initials: S
authors.lastname: Ihara
authors.forename: Motoko
authors.initials: M
authors.lastname: Takahashi
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Ide
authors.forename: Jianguo
authors.initials: J
authors.lastname: Gu
authors.forename: Hidenori
authors.initials: H
authors.lastname: Inohara
authors.forename: Taiichi
authors.initials: T
authors.lastname: Katayama
authors.forename: Masaya
authors.initials: M
authors.lastname: Tohyama
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kubo
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Taniguchi
authors.forename: Eiji
authors.initials: E
authors.lastname: Miyoshi
mesh_terms: D000595:Amino Acid Sequence; D053829:Amyloid Precursor Protein Secretases / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D017350:N-Acetylgalactosaminyltransferases / Q000737:chemistry / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D017354:Point Mutation; D053764:Presenilin-1 / Q000235:genetics / Q000378:metabolism; D053766:Presenilin-2 / Q000235:genetics / Q000378:metabolism; D000097763:Polypeptide N-acetylgalactosaminyltransferase
chemical_list: D053829:Amyloid Precursor Protein Secretases; D017350:N-Acetylgalactosaminyltransferases; D053764:Presenilin-1; D053766:Presenilin-2; D000097763:Polypeptide N-acetylgalactosaminyltransferase