scholarly journals Receptor tyrosine kinase Met promotes cell survival via kinase-independent maintenance of integrin α3β1

2016 ◽  
Vol 27 (15) ◽  
pp. 2493-2504 ◽  
Author(s):  
Lia Tesfay ◽  
Veronique V. Schulz ◽  
Sander B. Frank ◽  
Laura E. Lamb ◽  
Cindy K. Miranti

Matrix adhesion via integrins is required for cell survival. Adhesion of epithelial cells to laminin via integrin α3β1 was previously shown to activate at least two independent survival pathways. First, integrin α3β1 is required for autophagy-induced cell survival after growth factor deprivation. Second, integrin α3β1 independently activates two receptor tyrosine kinases, EGFR and Met, in the absence of ligands. EGFR signaling to Erk promotes survival independently of autophagy. To determine how Met promotes cell survival, we inhibited Met kinase activity or blocked its expression with RNA interference. Loss of Met expression, but not inhibition of Met kinase activity, induced apoptosis by reducing integrin α3β1 levels, activating anoikis, and blocking autophagy. Met was specifically required for the assembly of autophagosomes downstream of LC3II processing. Reexpression of wild-type Met, kinase-dead Met, or integrin α3 was sufficient to rescue death upon removal of endogenous Met. Integrin α3β1 coprecipitated and colocalized with Met in cells. The extracellular and transmembrane domain of Met was required to fully rescue cell death and restore integrin α3 expression. Thus Met promotes survival of laminin-adherent cells by maintaining integrin α3β1 via a kinase-independent mechanism.

IUBMB Life ◽  
2020 ◽  
Author(s):  
Xiangqi Fan ◽  
Xiangjun Xiao ◽  
Xiangbing Mao ◽  
Daiwen Chen ◽  
Bing Yu ◽  
...  

Biosensors ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 240
Author(s):  
Lan-Yi Wei ◽  
Wei Lin ◽  
Bey-Fen Leo ◽  
Lik-Voon Kiew ◽  
Chia-Ching Chang ◽  
...  

A miniature tyrosinase-based electrochemical sensing platform for label-free detection of protein tyrosine kinase activity was developed in this study. The developed miniature sensing platform can detect the substrate peptides for tyrosine kinases, such as c-Src, Hck and Her2, in a low sample volume (1–2 μL). The developed sensing platform exhibited a high reproducibility for repetitive measurement with an RSD (relative standard deviation) of 6.6%. The developed sensing platform can detect the Hck and Her2 in a linear range of 1–200 U/mL with the detection limit of 1 U/mL. The sensing platform was also effective in assessing the specificity and efficacies of the inhibitors for protein tyrosine kinases. This is demonstrated by the detection of significant inhibition of Hck (~88.1%, but not Her2) by the Src inhibitor 1, an inhibitor for Src family kinases, as well as the significant inhibition of Her2 (~91%, but not Hck) by CP-724714 through the platform. These results suggest the potential of the developed miniature sensing platform as an effective tool for detecting different protein tyrosine kinase activity and for accessing the inhibitory effect of various inhibitors to these kinases.


2010 ◽  
Vol 22 (5) ◽  
pp. 809-820 ◽  
Author(s):  
Balachandar Venkatesan ◽  
Sumanth D. Prabhu ◽  
Kaliyamurthi Venkatachalam ◽  
Srinivas Mummidi ◽  
Anthony J. Valente ◽  
...  

2008 ◽  
Vol 34 (6) ◽  
pp. 684-688 ◽  
Author(s):  
Gianrico Spagnuolo ◽  
Vincenzo D'Antò ◽  
Rosa Valletta ◽  
Caterina Strisciuglio ◽  
Gottfried Schmalz ◽  
...  

2017 ◽  
Vol 37 (5) ◽  
pp. 823-835 ◽  
Author(s):  
Christopher W. Smith ◽  
Steven G. Thomas ◽  
Zaher Raslan ◽  
Pushpa Patel ◽  
Maxwell Byrne ◽  
...  

Objective— Leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) is a collagen receptor that belongs to the inhibitory immunoreceptor tyrosine-based inhibition motif–containing receptor family. It is an inhibitor of signaling via the immunoreceptor tyrosine-based activation motif–containing collagen receptor complex, glycoprotein VI-FcRγ-chain. It is expressed on hematopoietic cells, including immature megakaryocytes, but is not detectable on platelets. Although the inhibitory function of LAIR-1 has been described in leukocytes, its physiological role in megakaryocytes and in particular in platelet formation has not been explored. In this study, we investigate the role of LAIR-1 in megakaryocyte development and platelet production by generating LAIR-1–deficient mice. Approach and Results— Mice lacking LAIR-1 exhibit a significant increase in platelet counts, a prolonged platelet half-life in vivo, and increased proplatelet formation in vitro. Interestingly, platelets from LAIR-1–deficient mice exhibit an enhanced reactivity to collagen and the glycoprotein VI–specific agonist collagen-related peptide despite not expressing LAIR-1, and mice showed enhanced thrombus formation in the carotid artery after ferric chloride injury. Targeted deletion of LAIR-1 in mice results in an increase in signaling downstream of the glycoprotein VI–FcRγ-chain and integrin αIIbβ3 in megakaryocytes because of enhanced Src family kinase activity. Conclusions— Findings from this study demonstrate that ablation of LAIR-1 in megakaryocytes leads to increased Src family kinase activity and downstream signaling in response to collagen that is transmitted to platelets, rendering them hyper-reactive specifically to agonists that signal through Syk tyrosine kinases, but not to G-protein–coupled receptors.


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