scholarly journals Membrane-associated periodic skeleton is a signaling platform for RTK transactivation in neurons

Science ◽  
2019 ◽  
Vol 365 (6456) ◽  
pp. 929-934 ◽  
Author(s):  
Ruobo Zhou ◽  
Boran Han ◽  
Chenglong Xia ◽  
Xiaowei Zhuang

Actin, spectrin, and related molecules form a membrane-associated periodic skeleton (MPS) in neurons. The function of the MPS, however, remains poorly understood. Using super-resolution imaging, we observed that G protein–coupled receptors (GPCRs), cell adhesion molecules (CAMs), receptor tyrosine kinases (RTKs), and related signaling molecules were recruited to the MPS in response to extracellular stimuli, resulting in colocalization of these molecules and RTK transactivation by GPCRs and CAMs, giving rise to extracellular signal–regulated kinase (ERK) signaling. Disruption of the MPS prevented such molecular colocalizations and downstream ERK signaling. ERK signaling in turn caused calpain-dependent MPS degradation, providing a negative feedback that modulates signaling strength. These results reveal an important functional role of the MPS and establish it as a dynamically regulated platform for GPCR- and CAM-mediated RTK signaling.

2019 ◽  
Author(s):  
Jeffrey S. Smith ◽  
Thomas F. Pack ◽  
Asuka Inoue ◽  
Claudia Lee ◽  
Xinyu Xiong ◽  
...  

SummaryG-protein-coupled receptors (GPCRs) enable cells to sense and respond appropriately to hormonal and environmental signals, and are a target of ~30% of all FDA-approved medications. Canonically, each GPCR couples to distinct Gα proteins, such as Gαs, Gαi, Gαq or Gα12/13, as well as β-arrestins. These transducer proteins translate and integrate extracellular stimuli sensed by GPCRs into intracellular signals through what are broadly considered separable signalling pathways. However, the ability of Gα proteins to directly interact with β-arrestins to integrate signalling has not previously been appreciated. Here we show a novel interaction between Gαi protein family members and β-arrestin. Gαi:β-arrestin complexes were formed by all GPCRs tested, regardless of their canonical G protein isoform coupling, and could bind both GPCRs as well as the extracellular signal-regulated kinase (ERK). This novel paradigm of Gαi:β-arrestin scaffolds enhances our understanding of GPCR signalling.


2001 ◽  
Vol 360 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Sandra BISOTTO ◽  
Elizabeth D. FIXMAN

The multisubstrate docking protein, growth-factor-receptor-bound protein 2-associated binder 1 (Gab1), which is phosphorylated on tyrosine residues following activation of receptor tyrosine kinases and cytokine receptors, regulates cell proliferation, survival and epithelial morphogenesis. Gab1 is also tyrosine phosphorylated following activation of G-protein-coupled receptors (GPCRs) where its function is poorly understood. To elucidate the role of Gab1 in GPCR signalling, we investigated the mechanism by which the type A endothelin-1 (ET-1) GPCR induced tyrosine phosphorylation of Gab1. Tyrosine phosphorylation of Gab1 induced by endothelin-1 was inhibited by PP1, a pharmacological inhibitor of Src-family tyrosine kinases. ET-1-induced Gab1 tyrosine phosphorylation was also inhibited by LY294002, which inhibits phosphoinositide 3-kinase (PI 3-kinase) enzymes. Inhibition of Src-family tyrosine kinases or PI 3-kinase also inhibited ET-1-induced activation of the mitogen activated protein kinase family member, extracellular signal-regulated kinase (ERK) 1. Thus we determined whether Gab1 regulated ET-1-induced ERK1 activation. Overexpression of wild-type Gab1 potentiated ET-1-induced activation of ERK1. Structure–function analyses of Gab1 indicated that mutant forms of Gab1 that do not bind the Src homology (SH) 2 domains of the p85 adapter subunit of PI 3-kinase or the SH2-domain-containing protein tyrosine phosphatase 2 (SHP-2) were impaired in their ability to potentiate ET-1-induced ERK1 activation. Taken together, our data indicate that PI 3-kinase and Src-family tyrosine kinases regulate ET-1-induced Gab1 tyrosine phosphorylation, which, in turn, induces ERK1 activation via PI 3-kinase- and SHP-2-dependent pathways.


2012 ◽  
Vol 40 (1) ◽  
pp. 251-256 ◽  
Author(s):  
Pamela A. Lochhead ◽  
Rebecca Gilley ◽  
Simon J. Cook

The MEK5 [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase 5]/ERK5 pathway is the least well studied MAPK signalling module. It has been proposed to play a role in the pathology of cancer. In the present paper, we review the role of the MEK5/ERK5 pathway using the ‘hallmarks of cancer’ as a framework and consider how this pathway is deregulated. As well as playing a key role in endothelial cell survival and tubular morphogenesis during tumour neovascularization, ERK5 is also emerging as a regulator of tumour cell invasion and migration. Several oncogenes can stimulate ERK5 activity, and protein levels are increased by a novel amplification at chromosome locus 17p11 and by down-regulation of the microRNAs miR-143 and miR-145. Together, these finding underscore the case for further investigation into understanding the role of ERK5 in cancer.


2005 ◽  
Vol 68 (2) ◽  
pp. 421-429 ◽  
Author(s):  
Vincent Pascoli ◽  
Emmanuel Valjent ◽  
Anne-Gaëlle Corbillé ◽  
Jean-Christophe Corvol ◽  
Jean-Pol Tassin ◽  
...  

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