title: Epidermal growth factor-induced mobilization of a ganglioside-specific sialidase (NEU3) to membrane ruffles.
abstract: Human ganglioside-specific sialidase, NEU3, localized at cell membranes is thought to regulate various biological processes at cell surfaces. We here explored functional subcellular localization of the sialidase by immunofluorescence and found accumulation at leading edges of cell membranes in the presence of serum in culture. In response to EGF, the sialidase redistributed rapidly to ruffling cell membranes of squamous carcinoma A431 cells and co-localized with Rac-1. NEU3 overexpression enhanced Rac-1 activation and cell migration as compared with controls in HeLa cells as well as in A431 cells. Consistent with co-localization with Rac-1 by immunofluorescence, NEU3 was found to co-precipitate with activated Rac bound to GST-PAK-1 fusion protein. NEU3 silencing by siRNA, in contrast, resulted in inhibition of Rac-1 activation. These results indicate that NEU3 is able to mobilize to membrane ruffles in response to growth stimuli and activate the Rac-1 signaling by co-localization with Rac-1, leading to increased cell motility.
authors.affiliation: Division of Biochemistry, Miyagi Cancer Center Research Institute, Natori, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Keiko
authors.initials: K
authors.lastname: Hata
authors.forename: Tadashi
authors.initials: T
authors.lastname: Wada
authors.forename: Setsuko
authors.initials: S
authors.lastname: Moriya
authors.forename: Taeko
authors.initials: T
authors.lastname: Miyagi
mesh_terms: D000818:Animals; D002460:Cell Line; D021961:Cell Membrane Structures / Q000378:metabolism*; D002465:Cell Movement; D002522:Chlorocebus aethiops; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000502:physiology*; D006801:Humans; D051379:Mice; D009439:Neuraminidase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport; D054462:p21-Activated Kinases; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: D004815:Epidermal Growth Factor; C515903:PAK1 protein, human; C515905:Pak1 protein, mouse; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases; C465436:Neu3 protein, human; D009439:Neuraminidase; D020830:rac1 GTP-Binding Protein