title: Echinophilic proteins stomatin, sorcin, and synexin locate outside gangliosideM1 (GM1) patches in the erythrocyte membrane.
abstract: The detergent (Triton X-100, 4°C)-resistant membrane (DRM)-associated membrane proteins stomatin, sorcin, and synexin (anexin VII) exposed on the cytoplasmic side of membrane were investigated for their lateral distribution in relation to induced ganglioside(M1) (GM1) raft patches in flat (discocytic) and curved (echinocytic) human erythrocyte membrane. In discocytes, no accumulation of stomatin, sorcin, and synexin in cholera toxin subunit B (CTB) plus anti-CTB-induced GM1 patches was detected by fluorescence microscopy. In echinocytes, stomatin, sorcin, and synexin showed a similar curvature-dependent lateral distribution as GM1 patches by accumulating to spiculae induced by ionophore A23187 plus calcium. Stomatin was partly and synexin and sorcin were fully recruited to the spiculae. However, the DRM-associated proteins only partially co-localized with GM1 and were frequently distributed into different spiculae than GM1. The study indicates that stomatin, sorcin, and synexin are echinophilic membrane components that mainly locate outside GM1 rafts in the human erythrocyte membrane. Echinophilicity is suggested to contribute to the DRM association of a membrane component in general.
authors.affiliation: Department of Cell Biology, A. Mickiewicz University, PL-61614, Poznań, Poland. lumro@amu.edu.pl
authors.forename: Lucyna
authors.initials: L
authors.lastname: Mrówczyńska
authors.forename: Ulrich
authors.initials: U
authors.lastname: Salzer
authors.forename: Sárka
authors.initials: S
authors.lastname: Perutková
authors.forename: Aleš
authors.initials: A
authors.lastname: Iglič
authors.forename: Henry
authors.initials: H
authors.lastname: Hägerstrand
mesh_terms: D017310:Annexin A7 / Q000737:chemistry / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D004910:Erythrocyte Membrane / Q000737:chemistry / Q000378:metabolism*; D004912:Erythrocytes / Q000166:cytology / Q000378:metabolism; D005677:G(M1) Ganglioside / Q000378:metabolism*; D006801:Humans; D021962:Membrane Microdomains / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D017830:Octoxynol / Q000737:chemistry
chemical_list: D017310:Annexin A7; D002135:Calcium-Binding Proteins; D008565:Membrane Proteins; C503113:SRI protein, human; C036860:STOM protein, human; D005677:G(M1) Ganglioside; D017830:Octoxynol