title: Lipid raft regulates the initial spreading of melanoma A375 cells by modulating β1 integrin clustering.
abstract: Cell adhesion and spreading require integrins-mediated cell-extracellular matrix interaction. Integrins function through binding to extracellular matrix and subsequent clustering to initiate focal adhesion formation and actin cytoskeleton rearrangement. Lipid raft, a liquid ordered plasma membrane microdomain, has been reported to play major roles in membrane motility by regulating cell surface receptor function. Here, we identified that lipid raft integrity was required for β1 integrin-mediated initial spreading of melanoma A375 cells on fibronectin. We found that lipid raft disruption with methyl-β-cyclodextrin led to the inability of focal adhesion formation and actin cytoskeleton rearrangement by preventing β1 integrin clustering. Furthermore, we explored the possible mechanism by which lipid raft regulates β1 integrin clustering and demonstrated that intact lipid raft could recruit and modify some adaptor proteins, such as talin, α-actinin, vinculin, paxillin and FAK. Lipid raft could regulate the location of these proteins in lipid raft fractions and facilitate their binding to β1 integrin, which may be crucial for β1 integrin clustering. We also showed that lipid raft disruption impaired A375 cell migration in both transwell and wound healing models. Together, these findings provide a new insight for the relationship between lipid raft and the regulation of integrins.
authors.affiliation: Institute of Genetics and Cytology, Northeast Normal University, Changchun 130024, China.
authors.forename: Ruifei
authors.initials: R
authors.lastname: Wang
authors.forename: Jiajia
authors.initials: J
authors.lastname: Bi
authors.forename: Khamal Kwesi
authors.initials: KK
authors.lastname: Ampah
authors.forename: Chunmei
authors.initials: C
authors.lastname: Zhang
authors.forename: Ziyi
authors.initials: Z
authors.lastname: Li
authors.forename: Yang
authors.initials: Y
authors.lastname: Jiao
authors.forename: Xiaoru
authors.initials: X
authors.lastname: Wang
authors.forename: Xueqing
authors.initials: X
authors.lastname: Ba
authors.forename: Xianlu
authors.initials: X
authors.lastname: Zeng
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D016000:Cluster Analysis; D005353:Fibronectins / Q000494:pharmacology; D022001:Focal Adhesions / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism*; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology*; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism*
chemical_list: D005353:Fibronectins; D019012:Integrin beta1
keywords: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; 4-morpholineethanesulfonic acid; Adaptor proteins; CTXB; DMEM; Dulbecco's modified Eagle's medium; ECM; EMT; FBS; Focal adhesion; Lipid raft; MES; MMPs; MTT; Melanoma cell spreading; MβCD; cholera toxin subunit B; epithelial–mesenchymal transition; extracellular matrix; fetal bovine serum; matrix metalloproteinases; methyl-β-cyclodextrin; siRNA; small interference RNA; β1 Integrin clustering