Integrin-Dependent Control of Inositol Lipid Synthesis in Vascular Endothelial Cells and Smooth Muscle Cells

McNamee, Helen P.; Liley, Helen; Ingber, Donald E.

doi:10.1006/excr.1996.0118

Cited by 37 publications

(36 citation statements)

References 16 publications

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“…Mechanical stresses applied to different receptors using magnetic micromanipulation result in molecular signaling that is strongly present only when the receptor stressed is cytoskeletally linked (2,(41)(42)(43). These results support the notion that cytoskeletally linked receptors serve as a link between the external mechanical environment and the internal signaling domains of the cell.…”

supporting

confidence: 72%

Cell stiffness and receptors: evidence for cytoskeletal subnetworks

Huang¹,

Sylvan²,

Jonas³

et al. 2005

American Journal of Physiology-Cell Physiology

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Viscoelastic models of cells often treat cells as homogeneous objects. However, studies have demonstrated that cellular properties are local and can change dramatically on the basis of the location probed. Because membrane receptors are linked in various ways to the intracellular space, with some receptors linking to the cytoskeleton and others diffusing freely without apparent linkages, the cellular physical response to mechanical stresses is expected to depend on the receptor engaged. In this study, we tested the hypothesis that cellular mechanical stiffness as measured via cytoskeletally linked receptors is greater than stiffness measured via receptors that are not cytoskeletally linked. We used a magnetic micromanipulator to apply linear stresses to magnetic beads attached to living cells via selected receptors. One of the receptor classes probed, the dystroglycan receptors, is linked to the cytoskeleton, while the other, the transferrin receptors, is not. Fibronectincoated beads were used to test cellular mechanical properties of the cytoskeleton without membrane dependence by allowing the beads to endocytose. For epithelial cells, transferrin-dependent stiffness and endocytosed bead-dependent stiffness were similar, while dystroglycan-dependent stiffness was significantly lower. For smooth muscle cells, dystroglycan-dependent stiffness was similar to the endocytosed bead-dependent stiffness, while the transferrin-dependent stiffness was lower. The conclusion of this study is that the measured cellular stiffness is critically influenced by specific receptor linkage and by cell type and raises the intriguing possibility of the existence of separate cytoskeletal networks with distinct mechanical properties that link different classes of receptors. magnetic micromanipulator; dystroglycan; transferrin THE MECHANISM BY WHICH CELLS sense and respond to mechanical forces is relevant to many pathological conditions, such as atherosclerosis and myopathies. While there is no consensus regarding the specific response mechanism, it is thought that the cytoskeleton plays an important role in sensing the cell's physical environment (9,32,33). To study the cellular response to mechanical stresses, different methods have been used, including membrane strain studies (6,8,11,15,28,37,39,50) and cone viscometer experiments (49). More recently, new techniques have allowed greater control of the applied forces and the targeting of specific membrane receptors (1,5,12,21,23,35,42,47,48). Magnetic micromanipulation applies stresses via magnetic beads and is capable of generating either linear (1, 4, 42) or twisting stress (10,43,44,52,53).Mechanical stresses applied to different receptors using magnetic micromanipulation result in molecular signaling that is strongly present only when the receptor stressed is cytoskeletally linked (2, 41-43). These results support the notion that cytoskeletally linked receptors serve as a link between the external mechanical environment and the internal signaling domains of the cell. Tensegrity-ba...

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supporting

confidence: 72%

Cell stiffness and receptors: evidence for cytoskeletal subnetworks

Huang¹,

Sylvan²,

Jonas³

et al. 2005

American Journal of Physiology-Cell Physiology

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“…PI(4,5)P 2 promotes formation of mature FAs by binding talin and vinculin and inducing their open state, where binding sites to other FA proteins and actin are exposed (32,33). PI(4,5)P 2 is locally generated in FAs by the enzyme phosphatidylinositol 4-phosphate 5-kinase type Iγ (PIP5KIγ) (34,35), which adds the 5-phosphate to PI(4)P. PIP5KIγ exists as two splice variants (PIP5KIγ661 and PIP5KIγ635 in mice), where the longer form (PIP5KIγ661, PIP5KIγ668 in humans) contains extra C-terminal residues that target the enzyme to FAs by interacting with the talin head domain (36,37).…”

Section: Significancementioning

confidence: 99%

Phosphatidylinositol 4,5-bisphosphate triggers activation of focal adhesion kinase by inducing clustering and conformational changes

Goñi

Epifano

Boskovic

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

126

186

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Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase (NRTK) with key roles in integrating growth and cell matrix adhesion signals, and FAK is a major driver of invasion and metastasis in cancer. Cell adhesion via integrin receptors is well known to trigger FAK signaling, and many of the players involved are known; however, mechanistically, FAK activation is not understood. Here, using a multidisciplinary approach, including biochemical, biophysical, structural, computational, and cell biology approaches, we provide a detailed view of a multistep activation mechanism of FAK initiated by phosphatidylinositol-4,5-bisphosphate [PI(4,5)P 2 ]. Interestingly, the mechanism differs from canonical NRTK activation and is tailored to the dual catalytic and scaffolding function of FAK. We find PI(4,5)P 2 induces clustering of FAK on the lipid bilayer by binding a basic region in the regulatory 4.1, ezrin, radixin, moesin homology (FERM) domain. In these clusters, PI(4,5)P 2 induces a partially open FAK conformation where the autophosphorylation site is exposed, facilitating efficient autophosphorylation and subsequent Src recruitment. However, PI(4,5)P 2 does not release autoinhibitory interactions; rather, Src phosphorylation of the activation loop in FAK results in release of the FERM/kinase tether and full catalytic activation. We propose that PI(4,5)P 2 and its generation in focal adhesions by the enzyme phosphatidylinositol 4-phosphate 5-kinase type Iγ are important in linking integrin signaling to FAK activation.cell signaling | phosphoinositides C ell attachment to the ECM is mediated via integrin transmembrane receptors on the cell surface. Integrin engagement to ECM components results in activation and clustering of integrins. In response to integrin activation, a large number of proteins are recruited to their cytoplasmic tails, resulting in the formation of focal adhesions (FAs) (1). On the one side, FAs are anchoring points for actomyosin stress fibers, which allow tension forces to build up when contracting fibers exert their pulling force via FAs against the ECM. On the other hand, integrin activation and the generation of tension trigger intricate signaling cascades. A central signaling component in FAs is the nonreceptor tyrosine kinase (NRTK) focal adhesion kinase (FAK).

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“…5, A and B). These results indicate that PLC inhibitors can disrupt cell spreading but the differential sensitivities to the two PLC inhibitors suggests that the PLC involved is phosphatidylcholine specific and not phosphatidylinositol specific, as would have been predicted from studies with adherent cell types such as epithelium, endothelium, and smooth muscle [13,14,29].…”

Section: Initiation and Maintenance Of Adhesion To Fn Is Sensitive Tomentioning

confidence: 63%

“…Although multiple studies have shown PLC-mediated activation of PKC in integrin signaling [13,14,29,34], no study has indicated a role for PC-PLC or shown a potential separation of the functional roles played by PC-PLC and PI-PLC. We found that D609 (a PC-PLC inhibitor) and not NEO (a PI-PLC inhibitor) significantly blocked cell spreading in HPB-ALL cells and PMA-activated PB-T cells on FN.…”

Section: Discussionmentioning

confidence: 99%

Separation of integrin-dependent adhesion from morphological changes based on differential PLC specificities

Wooten

Teague

McIntyre

1999

Journal of Leukocyte Biology

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In normal lymphocytes an inside-out signal up-regulating integrin adhesion is followed by a ligand-mediated outside-in cell spreading signal. Protein kinase C (PKC) inhibition blocks lymphocyte adherence to and spreading on fibronectin. In contrast, putative PLC inhibitors yield distinct differences with respect to adhesion and morphology. The phosphatidylinositol-specific phospholipase C (PLC) inhibitor neomycin blocked spreading of CD3/CD28-activated T cells on fibronectin by disrupting adhesion. Furthermore, when an additional inside-out signal for fibronectin adhesion is unnecessary such as with HPB-ALL T leukemic or phorbol-myristate-acetate-treated normal T cells, neomycin treatment does not alter adhesion or morphology. However, the phosphatidylcholinespecific PLC inhibitor D609 abrogates cell spreading without affecting adhesion to fibronectin in these cells as well as the CD3/CD28-activated T cells. These results strongly suggest that inside-out signaling for the integrin ␣ 4 ␤ 1 in lymphocytes proceeds through phosphatidylinositol-specific PLC and PKC, whereas the outside-in signal utilizes phosphatidylcholine-specific PLC and PKC. J. Leukoc. Biol. 65: 127-136; 1999.

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Integrin-Dependent Control of Inositol Lipid Synthesis in Vascular Endothelial Cells and Smooth Muscle Cells

Cited by 37 publications

References 16 publications

Cell stiffness and receptors: evidence for cytoskeletal subnetworks

Cell stiffness and receptors: evidence for cytoskeletal subnetworks

Phosphatidylinositol 4,5-bisphosphate triggers activation of focal adhesion kinase by inducing clustering and conformational changes

Separation of integrin-dependent adhesion from morphological changes based on differential PLC specificities

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