Molecular Basis of Kindlin-2 Binding to Integrin-linked Kinase Pseudokinase for Regulating Cell Adhesion

Fukuda, Koichi; Błędzka, Kamila; Yang, Jun; Perera, H. Dhanuja; Plow, Edward F.; Qin, Jun

doi:10.1074/jbc.m114.596692

Cited by 58 publications

(84 citation statements)

References 40 publications

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“…Kindlin-2, though not required for α5β1-mediated adhesion of endothelial cells (42), facilitates integrin αIIbβ3 clustering in Chinese hamster ovary cells during binding to fibrinogen (51). Additionally, the interactions between kindlin-2 and integrin-linked kinase are necessary for outside-in αIIbβ3 integrin signaling and cell adhesion, though mutations preventing this binding do not affect integrin activation (52). It is possible that T. gondii disrupts kindlin function in infected monocytes, dysregulating β1 integrin outside-in signaling, but not inside-out signaling.…”

Section: Discussionmentioning

confidence: 99%

Toxoplasma gondii disrupts β1 integrin signaling and focal adhesion formation during monocyte hypermotility

Cook¹,

Ueno²,

Lodoen

2018

Journal of Biological Chemistry

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The motility of blood monocytes is orchestrated by the activity of cell surface integrins, which translate extracellular signals into cytoskeletal changes to mediate adhesion and migration. Toxoplasma gondii is an intracellular parasite that infects migratory cells and enhances their motility, but the mechanisms underlying T. gondii-induced hypermotility are incompletely understood. We have investigated the molecular basis for the hypermotility of primary human peripheral blood monocytes and THP-1 cells infected with T. gondii. Compared to uninfected monocytes, T. gondii infection of monocytes reduced cell spreading and the number of activated β1 integrin clusters in contact with fibronectin during settling, an effect not observed in monocytes treated with LPS or E. coli. Furthermore, T. gondii infection disrupted the phosphorylation of focal adhesion kinase (FAK) at tyrosine 397 (Y397) and Y925 and of the related protein proline-rich tyrosine kinase (Pyk2) at Y402. The localization of paxillin, FAK, and vinculin to focal adhesions and the colocalization of these proteins with activated β1 integrins were also impaired in T. gondiiinfected monocytes. Using time-lapse confocal microscopy of THP-1 cells expressing eGFP-FAK during settling on fibronectin, we found that T. gondii-induced monocyte hypermotility was characterized by a reduced number of eGFP-FAKcontaining clusters over time compared to uninfected cells. This study demonstrates an integrin conformation-independent regulation of the β1 integrin adhesion pathway, providing further insight into the molecular mechanism of T. gondiiinduced monocyte hypermotility.

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Section: Discussionmentioning

confidence: 99%

Toxoplasma gondii disrupts β1 integrin signaling and focal adhesion formation during monocyte hypermotility

Cook¹,

Ueno²,

Lodoen

2018

Journal of Biological Chemistry

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“…Loss of kindlin-2 causes decreased ribosome production and thus leads to a dysfunction of fibroblasts. Recent studies showed that kindlin-2 localizes not only to focal adhesions but also to the nucleus, suggesting that kindlin-2 possesses functions in both focal adhesions and the nucleus (26,45,46). We recently found that kindlin-2 is critical for integrin outside-in signaling and Src activation (25).…”

Section: Discussionmentioning

confidence: 99%

Phosphatidylinositol 3-Kinase/Akt Mediates Integrin Signaling To Control RNA Polymerase I Transcriptional Activity

You

et al. 2016

Molecular and Cellular Biology

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c RNA polymerase I-mediated rRNA production is a key determinant of cell growth. Despite extensive studies, the signaling pathways that control RNA polymerase I-mediated rRNA production are not well understood. Here we provide original evidence showing that RNA polymerase I transcriptional activity is tightly controlled by integrin signaling. Furthermore, we show that a signaling axis consisting of focal adhesion kinase (FAK), Src, phosphatidylinositol 3-kinase (PI3K), Akt, and mTOR mediates the effect of integrin signaling on rRNA transcription. Additionally, we show that in kindlin-2 knockout mouse embryonic fibroblasts, overactivation of Ras, Akt, and Src can successfully rescue the defective RNA polymerase I activity induced by the loss of kindlin-2. Finally, through experiments with inhibitors of FAK, Src, and PI3K and rescue experiments in MEFs, we found that the FAK/Src/PI3K/Akt signaling pathway to control rRNA transcription is linear. Collectively, these studies reveal, for the first time, a pivotal role of integrin signaling in regulation of RNA polymerase I transcriptional activity and shed light on the downstream signaling axis that participates in regulation of this key aspect of cell growth. RNA polymerase I (Pol I) plays a central role in regulating cellular growth and proliferation (1). Eukaryotic cells contain hundreds of ribosomal DNA (rDNA) copies that occupy several different chromosomal locations (2). The production of rRNA can be divided into several steps, i.e., rRNA transcription, modification, and processing, all of which occur in the nucleolus (3, 4). The rate-limiting step is rRNA transcription (1, 5). On sensing of outside stimuli, a preinitiation complex comprised of the transcriptional factors upstream binding factor (UBF), SL1, TBP, Rrn3, and TTF assembles in the promoter region of rDNA. This complex then recruits RNA polymerase I to rDNA loci, and rRNA transcription starts (6-8). In mammalian cells, a single precursor rRNA transcript, 47S rRNA (14.3 kb), is transcribed from rDNA by the RNA polymerase I complex. This large polycistronic transcript encompasses 18S, 5.8S, and 28S rRNAs and includes several spacer regions, which are later processed into distinct rRNA species before assembly into preribosomal subunits (9).The transcriptional activity of Pol I is a fundamental determinant of cell proliferation capacity (3). In rapidly proliferating cells, rRNA production takes more than 50% of all nuclear transcriptional activity. In yeast cells, this percentage can reach more than 80% (10). As such, the tremendous energy consumption demands tight control.At the tissue level, cells attach to the extracellular matrix (ECM) through cell surface receptors termed integrins (11). Integrins are heterodimeric transmembrane receptors comprised of ␣ subunits and ␤ subunits that bind to extracellular ligands, such as laminin, collagen, vitronectin, and fibronectin. Different combinations of the 18 ␣ subunits and 8 ␤ subunits confer specificity on the integrin-ECM interactions (12). After binding ...

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“…A study in C. elegans proposed that binding of ILK to kindlin induced a conformational change of kindlin that promotes its binding to integrin tails (Qadota et al, 2012). This mechanism, however, has not been observed with mammalian kindlin orthologues (Huet-Calderwood et al, 2014;Fukuda et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…In contrast to talin, kindlins contain no obvious actin-binding sites; therefore, linkage to actin is mediated through their binding to the ILK-PINCH-parvin (IPP) complex and/or migfilin (also known as FBLIM1) (Mackinnon et al, 2002;Tu et al, 2003). Whereas the migfilin-binding site remains unknown, the ILK-binding site has been mapped to a short leucinerich, amphipathic α-helix between the F2 and PH domain of mammalian kindlins (Huet-Calderwood et al, 2014;Fukuda et al, 2014). The differential binding of kindlins to β-integrin tails is discussed in Box 1 and the binding sites for kindlin-interacting proteins are shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

The kindlin family: functions, signaling properties and implications for human disease

Rognoni

Ruppert

Fässler

2016

Journal of Cell Science

200

186

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The kindlin (or fermitin) family of proteins comprises three members (kindlin-1,-2 and -3) of evolutionarily conserved focal adhesion (FA) proteins, whose best-known task is to increase integrin affinity for a ligand (also referred as integrin activation) through binding of β-integrin tails. The consequence of kindlin-mediated integrin activation and integrin-ligand binding is cell adhesion, spreading and migration, assembly of the extracellular matrix (ECM), cell survival, proliferation and differentiation.

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Molecular Basis of Kindlin-2 Binding to Integrin-linked Kinase Pseudokinase for Regulating Cell Adhesion

Cited by 58 publications

References 40 publications

Toxoplasma gondii disrupts β1 integrin signaling and focal adhesion formation during monocyte hypermotility

Toxoplasma gondii disrupts β1 integrin signaling and focal adhesion formation during monocyte hypermotility

Phosphatidylinositol 3-Kinase/Akt Mediates Integrin Signaling To Control RNA Polymerase I Transcriptional Activity

The kindlin family: functions, signaling properties and implications for human disease

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