scholarly journals Revising Endosomal Trafficking under Insulin Receptor Activation

2021 ◽  
Vol 22 (13) ◽  
pp. 6978
Author(s):  
Maria J. Iraburu ◽  
Tommy Garner ◽  
Cristina Montiel-Duarte

The endocytosis of ligand-bound receptors and their eventual recycling to the plasma membrane (PM) are processes that have an influence on signalling activity and therefore on many cell functions, including migration and proliferation. Like other tyrosine kinase receptors (TKR), the insulin receptor (INSR) has been shown to be endocytosed by clathrin-dependent and -independent mechanisms. Once at the early endosome (EE), the sorting of the receptor, either to the late endosome (LE) for degradation or back to the PM through slow or fast recycling pathways, will determine the intensity and duration of insulin effects. Both the endocytic and the endosomic pathways are regulated by many proteins, the Arf and Rab families of small GTPases being some of the most relevant. Here, we argue for a specific role for the slow recycling route, whilst we review the main molecular mechanisms involved in INSR endocytosis, sorting and recycling, as well as their possible role in cell functions.

2010 ◽  
Vol 30 (15) ◽  
pp. 3795-3804 ◽  
Author(s):  
Nicholas Ariotti ◽  
Hong Liang ◽  
Yufei Xu ◽  
Yueqiang Zhang ◽  
Yoshiya Yonekubo ◽  
...  

ABSTRACT Signal transduction is regulated by the lateral segregation of proteins into nanodomains on the plasma membrane. However, the molecular mechanisms that regulate the lateral segregation of cell surface receptors, such as receptor tyrosine kinases, upon ligand binding are unresolved. Here we used high-resolution spatial mapping to investigate the plasma membrane nanoscale organization of the epidermal growth factor (EGF) receptor (EGFR). Our data demonstrate that in serum-starved cells, the EGFR exists in preformed, cholesterol-dependent, actin-independent nanoclusters. Following stimulation with EGF, the number and size of EGFR nanoclusters increase in a time-dependent manner. Our data show that the formation of EGFR nanoclusters requires receptor tyrosine kinase activity. Critically, we show for the first time that production of phosphatidic acid by phospholipase D2 (PLD2) is essential for ligand-induced EGFR nanocluster formation. In accordance with its crucial role in regulating EGFR nanocluster formation, we demonstrate that modulating PLD2 activity tunes the degree of EGFR nanocluster formation and mitogen-activated protein kinase signal output. Together, these data show that EGFR activation drives the formation of signaling domains by regulating the production of critical second-messenger lipids and modifying the local membrane lipid environment.


1993 ◽  
Vol 340 (1293) ◽  
pp. 267-271 ◽  

Rho-related proteins are members of the ras superfamily of small GTP-binding proteins. Their function in fibroblasts has been analysed using microinjection of living cells. Rho appears to link plasma membrane receptors to the assembly of focal adhesions and actin stress fibres. The closely related protein rac, on the other hand, links receptors to the polymerization of actin at the plasma membrane to form membrane ruffles and pinocytotic vesicles. In phagocytic cells, rac has been shown to be required for activation of a membrane-bound NADPH oxidase in response to receptor activation. These systems provide the basis for a working model for the mechanism of action of the rho family of small GTPases.


1996 ◽  
Vol 16 (5) ◽  
pp. 1946-1954 ◽  
Author(s):  
L V Lotti ◽  
L Lanfrancone ◽  
E Migliaccio ◽  
C Zompetta ◽  
G Pelicci ◽  
...  

The intracellular localization of Shc proteins was analyzed by immunofluorescence and immunoelectron microscopy in normal cells and cells expressing the epidermal growth factor receptor or the EGFR/erbB2 chimera. In unstimulated cells, the immunolabeling was localized in the central perinuclear area of the cell and mostly associated with the cytosolic side of rough endoplasmic reticulum membranes. Upon epidermal growth factor treatment and receptor tyrosine kinase activation, the immunolabeling became peripheral and was found to be associated with the cytosolic surface of the plasma membrane and endocytic structures, such as coated pits and endosomes, and with the peripheral cytosol. Receptor activation in cells expressing phosphorylation-defective mutants of Shc and erbB-2 kinase showed that receptor autophosphorylation, but not Shc phosphorylation, is required for redistribution of Shc proteins. The rough endoplasmic reticulum localization of Shc proteins in unstimulated cells and their massive recruitment to the plasma membrane, endocytic structures, and peripheral cytosol following receptor tyrosine kinase activation could account for multiple putative functions of the adaptor protein.


2020 ◽  
Author(s):  
Miwa Umebayashi ◽  
Satoko Takemoto ◽  
Luc Reymond ◽  
Mayya Sundukova ◽  
Ruud Hovius ◽  
...  

AbstractFunctional membrane proteins in the plasma membrane are suggested to have specific membrane environments that play important roles to maintain and regulate the function of proteins. However, the local membrane environments of membrane proteins remain largely unexplored due to the lack of techniques allowing to monitor them in living cells. We have developed a method to probe the local membrane environment surrounding a membrane protein in the plasma membrane by covalently tethering a solvatochromic, environment-sensitive dye, Nile red, to a membrane protein via a flexible linker. Our direct imaging reported on the spatio-temporal properties of membrane fluidity of the local environment surrounding the insulin receptor. The local environment was distinct from the average plasma membrane fluidity and was quite dynamic and heterogeneous. Upon addition of insulin, the local membrane environment surrounding the receptor increased in fluidity in an insulin receptor-kinase dependent manner. This new technology should allow researchers to examine changes in membrane properties caused by receptor activation and devise ways to address the role of these changes in physiological processes.


1995 ◽  
Vol 306 (2) ◽  
pp. 465-472 ◽  
Author(s):  
I Leconte ◽  
E Clauser

The tyrosine kinase domain of the human insulin receptor (IR) contains several short amino acid motifs which are strictly conserved in all protein kinases and two sequence motifs which are specific to the tyrosine kinases (AAR or RAA and P(I)/VK/RWT/M). In the serine/threonine kinases these motifs are replaced by the sequences KPE and GT/SXXY/PX respectively. In the present work, the tyrosine kinase-specific sequences of the IR (1134AAR1136 and 1172PVRWM1176) were replaced using site-directed mutagenesis by sequences which confer a serine kinase specificity on the receptor. Five different IR mutants were expressed in Chinese hamster ovary (CHO) or COS cells and their structural and functional properties compared with those of the wild-type recombinant human IR. These mutants are processed normally and bind insulin with normal affinities. None of the mutants containing a putative serine kinase-specific sequence display detectable autophosphorylation or tyrosine kinase activity in response to insulin, either in vitro or in vivo. These mutants were also unable to phosphorylate serine/threonine kinase substrates after insulin stimulation. Unexpectedly, they showed impaired ATP binding, as studied by an original technique consisting of cross-linking adenosine 5′-([35S]thio)triphosphate to partially purified receptors. Finally, none of the studied mutants transmit the insulin signal necessary to stimulate either DNA or glycogen synthesis. These data provide evidence for the importance of these conserved sequences in the kinase domain for both receptor activation and kinase activity. Furthermore, they demonstrate that the exchange of sequences specific to the catalytic domain of tyrosine kinases for those specific to the serine/threonine kinases is not sufficient to confer serine/threonine specificity on the insulin receptor.


1997 ◽  
Vol 272 (6) ◽  
pp. 3554-3559 ◽  
Author(s):  
Chengbiao Wu ◽  
Stefan Butz ◽  
Yun-shu Ying ◽  
Richard G. W. Anderson

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