Dataset Information

Protein 4.1G Regulates Cell Adhesion, Spreading, and Migration of Mouse Embryonic Fibroblasts through the ?1 Integrin Pathway.

ABSTRACT: Protein 4.1G is a membrane skeletal protein that can serve as an adapter between transmembrane proteins and the underlying membrane skeleton. The function of 4.1G remains largely unexplored. Here, using 4.1G knockout mouse embryonic fibroblasts (MEFs) as a model system, we explored the function of 4.1G in motile cells. We show that the adhesion, spreading, and migration of 4.1G(-/-) MEF cells are impaired significantly. We further show that, although the total cellular expression of ?1 integrin is unchanged, the surface expression of ?1 integrin and its active form are decreased significantly in 4.1G(-/-) MEF cells. Moreover, the phosphorylation of focal adhesion kinase, a downstream component of the integrin-mediated signal transduction pathway, is suppressed in 4.1G(-/-) MEF cells. Co-immunoprecipitation experiments and in vitro binding assays showed that 4.1G binds directly to ?1 integrin via its membrane-binding domain. These findings identified a novel role of 4.1G in cell adhesion, spreading, and migration in MEF cells by modulating the surface expression of ?1 integrin and subsequent downstream signal transduction.

SUBMITTER: Chen L

PROVIDER: S-EPMC4732203 | biostudies-literature | 2016 Jan

REPOSITORIES: biostudies-literature

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Protein 4.1G Regulates Cell Adhesion, Spreading, and Migration of Mouse Embryonic Fibroblasts through the β1 Integrin Pathway.

Chen Lixiang L Wang Ting T Wang Yaomei Y Zhang Jingxin J Qi Yuanming Y Weng Haibo H Kang Qiaozhen Q Guo Xinhua X Baines Anthony J AJ Mohandas Narla N An Xiuli X

The Journal of biological chemistry 20151207 5

Protein 4.1G is a membrane skeletal protein that can serve as an adapter between transmembrane proteins and the underlying membrane skeleton. The function of 4.1G remains largely unexplored. Here, using 4.1G knockout mouse embryonic fibroblasts (MEFs) as a model system, we explored the function of 4.1G in motile cells. We show that the adhesion, spreading, and migration of 4.1G(-/-) MEF cells are impaired significantly. We further show that, although the total cellular expression of β1 integrin ...[more]

PMID: 26644476

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Project description:Adhesive and migratory behavior can be cell type, integrin, and substrate dependent. We have compared integrin and substrate differences using three integrin receptors: ?5?1, ?6?1, and ?L?2 expressed in a common cell type, CHO.B2 cells, which lack integrin ? subunits, as well as in different cell types that express one or more of these integrins. We find that CHO.B2 cells expressing either ?6?1 or ?L?2 integrins migrate and protrude faster and are more directionally persistent on laminin or ICAM-1, respectively, than CHO.B2 cells expressing ?5?1 on fibronectin. Despite rapid adhesion maturation and the presence of large adhesions in both the ?6?1- and ?L?2-expressing cells, they display robust tyrosine phosphorylation. In addition, whereas myosin II regulates adhesion maturation and turnover, protrusion rates, and polarity in cells migrating on fibronectin, surprisingly, it does not have comparable effects in cells expressing ?6?1 or ?L?2. This apparent difference in the integration of myosin II activity, adhesion, and migration arises from alterations in the ligand-integrin-actin linkage (molecular clutch). The elongated adhesions in the protrusions of the ?6?1-expressing cells on laminin or the ?L?2-expressing cells on ICAM-1 display a novel, rapid retrograde flux of integrin; this was largely absent in the large adhesions in protrusions of ?5?1-expressing cells on fibronectin. Furthermore, the force these adhesions exert on the substrate in protrusive regions is reduced compared to similar regions in ?5-expressing cells, and the adhesion strength is reduced. This suggests that intracellular forces are not efficiently transferred from actomyosin to the substratum due to altered adhesion strength, that is, avidity, affinity, or the ligand-integrin-actin interaction. Finally, we show that the migration of fast migrating leukocytes on fibronectin or ICAM-1 is also largely independent of myosin II; however, their adhesions are small and do not show retrograde fluxing suggesting other intrinsic factors determine their migration differences.

Dataset Information

Protein 4.1G Regulates Cell Adhesion, Spreading, and Migration of Mouse Embryonic Fibroblasts through the ?1 Integrin Pathway.

Publications

Protein 4.1G Regulates Cell Adhesion, Spreading, and Migration of Mouse Embryonic Fibroblasts through the β1 Integrin Pathway.

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