Differential calreticulin expression affects focal contacts via the calmodulin/CaMK II pathway

Szabó, Éva; Papp, Sylvia; Opas, Michał

doi:10.1002/jcp.21122

Cited by 25 publications

(24 citation statements)

References 53 publications

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“…CaMKII associates with filamentous actin and cytochalasin D abolishes this association [80]. Increased activity of CaMKII (as in the case of cytochalasin D treatment) has been shown to diminish cell adhesiveness [81][82][83], and we observe an association between activation of CaMKII and increased cell rounding [12,32,34,79]. CaMKII activation reduces cell adhesiveness by promoting dephosphorylation of focal adhesion kinase and paxillin [83], which reduces their incorporation into focal adhesions and may promote adipogenesis [11,84,85].…”

Section: Es Cell Shape and Adhesion Modulate Intracellular Signallingmentioning

confidence: 56%

“…In contrast, nocodazole decreases the activity of CaMKII, which may have multiple, stimulatory effects on cell adhesion. Decreasing the activity of CaMKII may increase focal adhesion-based cellsubstratum adhesion as described before [12,32,34,79,81,83]. Inactivation of c-Src by microtubule depolymerization may help in inhibiting CaMKII activity as c-Src is one of the activators of the CaMKII signalling pathway [19,20].…”

Section: Es Cell Shape and Adhesion Modulate Intracellular Signallingmentioning

confidence: 99%

“…This effect, however, has been related to cell rounding. In addition, in the absence of calreticulin, all cell types examined so far are poorly spread and have higher levels of activated CaMKII than their calreticulincontaining counterparts [17,32,34,79].…”

Section: Es Cell Shape and Adhesion Modulate Intracellular Signallingmentioning

confidence: 99%

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Cytoskeletal Disassembly and Cell Rounding Promotes Adipogenesis from ES Cells

Feng

Szabó

Dziak

et al. 2010

Stem Cell Rev and Rep

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Biomechanical signals such as cell shape and spreading play an important role in controlling stem cell commitment. Cell shape, adhesion and spreading are also affected by calreticulin, a multifunctional calcium-binding protein, which influences several cellular processes, including adipogenesis. Here we show that cytoskeletal disruption in mouse embryonic stem cells using cytochalasin D or nocodazole promotes adipogenesis. While cytochalasin D disrupts stress fibres and inhibits focal adhesion formation, nocodazole depolymerises microtubules and promotes focal adhesion formation. Furthermore, cytochalasin D increases the levels of both total and activated calcium/calmodulin-dependent protein kinase II, whereas nocodazole decreases it. Nevertheless, both treatments significantly increase the adipogenic potential of embryonic stem cells in vitro. Both cytochalasin D and nocodazole exposure caused cell rounding suggesting that it is cell shape that causes the switch towards the adipogenic programme. Calreticulin-containing embryonic stem cells, under baseline conditions, show low adipogenic potential, have low activity of signalling via calcium/calmodulin-dependent protein kinase II and display normal adhesive properties and cellular spreading in comparison to the highly adipogenic but poorly spread calreticulin-deficient ES cells. We conclude that forced cell rounding via cytoskeletal disruption overrides the effects of calreticulin, an ER chaperone, thus negatively regulating adipogenesis via focal adhesion-mediated cell spreading.

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Section: Es Cell Shape and Adhesion Modulate Intracellular Signallingmentioning

confidence: 56%

Section: Es Cell Shape and Adhesion Modulate Intracellular Signallingmentioning

confidence: 99%

See 1 more Smart Citation

Cytoskeletal Disassembly and Cell Rounding Promotes Adipogenesis from ES Cells

Feng

Szabó

Dziak

et al. 2010

Stem Cell Rev and Rep

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“…19,20 Cells underexpressing CRT have increased expression of calmodulin, activated CAMKII (calmodulin-dependent kinase II), and c-src, causing weak adhesion and spreading via focal contacts. 18,20,82 Furthermore, CRT null mouse embryo fibroblasts demonstrate decreased ability to migrate on fibronectin and laminin. 17 Whereas GFP-CRT expression was not localized to focal contacts, one study shows that CRT and another ER-resident protein, RAP (low-density LRP receptor-associated protein) are associated with integrin-based cellular adhesion complexes that link to the cytoskeleton, containing such signaling proteins as vinculin, talin, paxillin, focal adhesion kinase, and ␣-actinin.…”

Section: Discussionmentioning

confidence: 99%

Calreticulin Enhances Porcine Wound Repair by Diverse Biological Effects

Nanney

Woodrell

Greives

et al. 2008

The American Journal of Pathology

137

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Extracellular functions of the endoplasmic reticulum chaperone protein calreticulin (CRT) are emerging. Here we show novel roles for exogenous CRT in both cutaneous wound healing and diverse processes associated with repair. Compared with platelet-derived growth factor-BB-treated controls, topical application of CRT to porcine excisional wounds enhanced the rate of wound re-epithelialization. In both normal and steroid-impaired pigs, CRT increased granulation tissue formation. Immunohistochemical analyses of the wounds 5 and 10 days after injury revealed marked up-regulation of transforming growth factor-␤3 (a key regulator of wound healing), a threefold increase in macrophage influx, and an increase in the cellular proliferation of basal keratinocytes of the new epidermis and of cells of the neodermis. In vitro studies confirmed that CRT induced a greater than twofold increase in the cellular proliferation of primary human keratinocytes, fibroblasts, and microvascular endothelial cells (with 100 pg/ml, 100 ng/ ml, and 1.0 pg/ml, respectively). Moreover, using a scratch plate assay, CRT maximally induced the cellular migration of keratinocytes and fibroblasts (with 10 pg/ml and 1 ng/ml, respectively). In addition, CRT induced concentration-dependent migration of keratinocytes, fibroblasts macrophages, and monocytes in chamber assays. These in vitro bioactivities provide mechanistic support for the positive biological effects of CRT observed on both the epidermis and dermis of wounds in vivo, underscoring a significant role for

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“…This multifunctional protein participates in calcium homeostasis via its high calcium storage capacity, in protein "quality control" via its chaperoning activity, and in cell adhesion via pathways that are still not entirely clear [7,8]. It is known that the level of calreticulin expression affects adherens-type adhesions i.e., focal contacts and zonula adherens [9], by regulating the expression of their structural proteins, namely the focal contact protein vinculin, the zonula adherens protein, N-cadherin and the ECM protein, fibronectin [10][11][12][13][14][15]. Clustering of the integrin  5 β 1 (fibronectin receptor) is also affected by the level of calreticulin expression [14].…”

Section: Introductionmentioning

confidence: 99%

Calreticulin affects cell adhesiveness through differential phosphorylation of insulin receptor substrate-1

Czarnowski

Papp

Száraz

et al. 2014

Cellular and Molecular Biology Letters

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Cellular adhesion to the underlying substratum is regulated through numerous signaling pathways. It has been suggested that insulin receptor substrate 1 (IRS-1) is involved in some of these pathways, via association with and activation of transmembrane integrins. Calreticulin, as an important endoplasmic reticulum-resident, calcium-binding protein with a chaperone function, plays an obvious role in proteomic expression. Our previous work showed that calreticulin mediates cell adhesion not only by affecting protein expression but also by affecting the state of regulatory protein phosphorylation, such as that of c-src. Here, we demonstrate that calreticulin affects the abundance of IRS-1 such that the absence of calreticulin is paralleled by a decrease in IRS-1 levels and the unregulated overexpression of calreticulin is accompanied by an increase in IRS-1 levels. These changes in the abundance of calreticulin and IRS-1 are accompanied by changes in cell-substratum adhesiveness and phosphorylation, such that increases in the expression of calreticulin and IRS-1 are paralleled by an increase in focal contact-based cellsubstratum adhesiveness, and a decrease in the expression of these proteins brings about a decrease in cell-substratum adhesiveness. Wild type and calreticulin-null mouse embryonic fibroblasts (MEFs) were cultured and the IRS-1 isoform profile was assessed. Differences in morphology and motility were also quantified. While no substantial differences in the speed of locomotion were found, the directionality of cell movement was greatly promoted by the presence of calreticulin. Calreticulin expression was also found to have a dramatic effect on the phosphorylation state of serine 636 of IRS-1, such that phosphorylation of IRS-1 on serine 636 increased radically in the absence of calreticulin. Most importantly, treatment of cells with the RhoA/ROCK inhibitor, Y-27632, which among its many effects also inhibited serine 636 phosphorylation of IRS-1, had profound effects on cell-substratum adhesion, in that it suppressed focal contacts, induced extensive close contacts, and increased the strength of adhesion. The latter effect, while counterintuitive, can be explained by the close contacts comprising labile bonds but in large numbers. In addition, the lability of bonds in close contacts would permit fast locomotion. An interesting and novel finding is that Y-27632 treatment of MEFs releases them from contact inhibition of locomotion, as evidenced by the invasion of a cell's underside by the thin lamellae and filopodia of a cell in close apposition.

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Differential calreticulin expression affects focal contacts via the calmodulin/CaMK II pathway

Cited by 25 publications

References 53 publications

Cytoskeletal Disassembly and Cell Rounding Promotes Adipogenesis from ES Cells

Cytoskeletal Disassembly and Cell Rounding Promotes Adipogenesis from ES Cells

Calreticulin Enhances Porcine Wound Repair by Diverse Biological Effects

Calreticulin affects cell adhesiveness through differential phosphorylation of insulin receptor substrate-1

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