scholarly journals Rapid whole cell imaging reveals a calcium-APPL1-dynein nexus that regulates cohort trafficking of stimulated EGF receptors

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
H. M. York ◽  
A. Patil ◽  
U. K. Moorthi ◽  
A. Kaur ◽  
A. Bhowmik ◽  
...  
Keyword(s):  
Signal Processing ◽  
Growth Factor ◽  
Leucine Zipper ◽  
Adaptor Protein ◽  
Endosomal Trafficking ◽  
Egf Receptors ◽  
Ph Domain ◽  
Cell Level ◽  
Whole Cell ◽  
Light Sheet Microscopy

AbstractThe endosomal system provides rich signal processing capabilities for responses elicited by growth factor receptors and their ligands. At the single cell level, endosomal trafficking becomes a critical component of signal processing, as exemplified by the epidermal growth factor (EGF) receptors. Activated EGFRs are trafficked to the phosphatase-enriched peri-nuclear region (PNR), where they are dephosphorylated and degraded. The details of the mechanisms that govern the movements of stimulated EGFRs towards the PNR, are not completely known. Here, exploiting the advantages of lattice light-sheet microscopy, we show that EGFR activation by EGF triggers a transient calcium increase causing a whole-cell level redistribution of Adaptor Protein, Phosphotyrosine Interacting with PH Domain And Leucine Zipper 1 (APPL1) from pre-existing endosomes within one minute, the rebinding of liberated APPL1 directly to EGFR, and the dynein-dependent translocation of APPL1-EGF-bearing endosomes to the PNR within ten minutes. The cell spanning, fast acting network that we reveal integrates a cascade of events dedicated to the cohort movement of activated EGF receptors. Our findings support the intriguing proposal that certain endosomal pathways have shed some of the stochastic strategies of traditional trafficking and have evolved processes that provide the temporal predictability that typify canonical signaling.

scholarly journals Rapid Whole Cell Imaging Reveals A Calcium-APPL1-Dynein Nexus That Regulates Cohort Trafficking of Stimulated EGF Receptors

2018 ◽  
Author(s):  
H M York ◽  
A Patil ◽  
U K Moorthi ◽  
A Kaur ◽  
A Bhowmik ◽  
...  
Keyword(s):  
Signal Processing ◽  
Cell Imaging ◽  
Light Sheet ◽  
Endosomal Trafficking ◽  
Egf Receptors ◽  
Whole Cell ◽  
Cellular Processes ◽  
Light Sheet Microscopy ◽  
Signaling Receptors ◽  
Cell Surface Signaling

ABSTRACTMulticellular life processes such as proliferation and differentiation depend on cell surface signaling receptors that bind ligands generally referred to as growth factors. Recently, it has emerged that the endosomal system provides rich signal processing capabilities for responses elicited by these factors [1-3]. At the single cell level, endosomal trafficking becomes a critical component of signal processing, as exemplified by the epidermal growth factor (EGF) receptors of the receptor tyrosine kinase family. EGFRs, once activated by EGF, are robustly trafficked to the phosphatase-enriched peri-nuclear region (PNR), where they are dephosphorylated [4-8]. However, the details of the mechanisms regulating the movements of stimulated EGFR in time and space, i.e., towards the PNR, are not known. What endosomal regulators provide specificity to EGFR? Do modifications to the receptor upon stimulation regulate its trafficking? To understand the events leading to EGFR translocation, and especially the early endosomal dynamics that immediately follow EGFR internalization, requires the real-time, long-term, whole-cell imaging of multiple elements. Here, exploiting the advantages of lattice light-sheet microscopy [9], we show that the binding of EGF by its receptor, EGFR, triggers a transient calcium increase that peaks by 30 s, causing the desorption of APPL1 from pre-existing endosomes within one minute, the rebinding of liberated APPL1 to EGFR within three minutes, and the dynein-dependent translocation of APPL1-EGF-bearing endosomes to the PNR within five minutes. The novel, cell spanning, fast acting network that we reveal integrates a cascade of events dedicated to the cohort movement of activated EGFR receptors. Our findings support the intriguing proposal that certain endosomal pathways have shed some of the stochastic strategies of traditional trafficking, and have evolved behaviors whose predictability is better suited to signaling [10, 11]. Work presented here demonstrates that our whole cell imaging approach can be a powerful tool in revealing critical transient interactions in key cellular processes such as receptor trafficking.

scholarly journals Filopodia formation and endosome clustering induced by mutant plus-end–directed myosin VI

2017 ◽  
Vol 114 (7) ◽  
pp. 1595-1600 ◽  
Author(s):  
Thomas A. Masters ◽  
Folma Buss
Keyword(s):  
Actin Filaments ◽  
Leucine Zipper ◽  
Adaptor Protein ◽  
Cell Cortex ◽  
Myosin Vi ◽  
Actin Network ◽  
Ph Domain ◽  
Cortical Actin ◽  
Directed Movement ◽  
Interacting Protein

Myosin VI (MYO6) is the only myosin known to move toward the minus end of actin filaments. It has roles in numerous cellular processes, including maintenance of stereocilia structure, endocytosis, and autophagosome maturation. However, the functional necessity of minus-end–directed movement along actin is unclear as the underlying architecture of the local actin network is often unknown. To address this question, we engineered a mutant of MYO6, MYO6+, which undergoes plus-end–directed movement while retaining physiological cargo interactions in the tail. Expression of this mutant motor in HeLa cells led to a dramatic reorganization of cortical actin filaments and the formation of actin-rich filopodia. MYO6 is present on peripheral adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1 (APPL1) signaling endosomes and MYO6+ expression causes a dramatic relocalization and clustering of this endocytic compartment in the cell cortex. MYO6+ and its adaptor GAIP interacting protein, C terminus (GIPC) accumulate at the tips of these filopodia, while APPL1 endosomes accumulate at the base. A combination of MYO6+ mutagenesis and siRNA-mediated depletion of MYO6 binding partners demonstrates that motor activity and binding to endosomal membranes mediated by GIPC and PI(4,5)P2 are crucial for filopodia formation. A similar reorganization of actin is induced by a constitutive dimer of MYO6+, indicating that multimerization of MYO6 on endosomes through binding to GIPC is required for this cellular activity and regulation of actin network structure. This unique engineered MYO6+ offers insights into both filopodia formation and MYO6 motor function at endosomes and at the plasma membrane.

Phosphoinositide 3-kinase-dependent phosphorylation of the dual adaptor for phosphotyrosine and 3-phosphoinositides by the Src family of tyrosine kinase

2000 ◽  
Vol 349 (2) ◽  
pp. 605-610 ◽  
Author(s):  
Simon DOWLER ◽  
Leire MONTALVO ◽  
Doreen CANTRELL ◽  
Nick MORRICE ◽  
Dario R. ALESSI
Keyword(s):  
Growth Factor ◽  
Tyrosine Kinase ◽  
Active Form ◽  
Adaptor Protein ◽  
Sh2 Domain ◽  
Ph Domain ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells ◽  
Phosphoinositide 3 Kinase

We recently identified a novel adaptor protein, termed dual adaptor for phosphotyrosine and 3-phosphoinositides (DAPP1), that possesses a Src homology (SH2) domain and a pleckstrin homology (PH) domain. DAPP1 exhibits a high-affinity interaction with PtdIns(3,4,5)P3 and PtdIns(3,4)P2, which bind to the PH domain. In the present study we show that when DAPP1 is expressed in HEK-293 cells, the agonists insulin, insulin-like growth factor-1 and epidermal growth factor induce the phosphorylation of DAPP1 at Tyr139. Treatment of cells with phosphoinositide 3-kinase (PI 3-kinase) inhibitors or expression of a dominant-negative PI 3-kinase prevent phosphorylation of DAPP1 at Tyr139, and a PH-domain mutant of DAPP1, which does not interact with PtdIns(3,4,5)P3 or PtdIns(3,4)P2, is not phosphorylated at Tyr139 following agonist stimulation of cells. Overexpression of a constitutively active form of PI 3-kinase induced the phosphorylation of DAPP1 in unstimulated cells. We demonstrated that Tyr139 of DAPP1 is likely to be phosphorylated in vivo by a Src-family tyrosine kinase, since the specific Src-family inhibitor, PP2, but not an inactive variant of this drug, PP3, prevented the agonist-induced tyrosine phosphorylation of DAPP1. Src, Lyn and Lck tyrosine kinases phosphorylate DAPP1 at Tyr139in vitro at similar rates in the presence or absence of PtdIns(3,4,5)P3, and overexpression of these kinases in HEK-293 cells induces the phosphorylation of Tyr139. These findings indicate that, following activation of PI 3-kinases, PtdIns(3,4,5)P3 or PtdIns(3,4)P2 bind to DAPP1, recruiting it to the plasma membrane where it becomes phosphorylated at Tyr139 by a Src-family tyrosine kinase.

scholarly journals APPL1 is a multifunctional endosomal signaling adaptor protein

2017 ◽  
Vol 45 (3) ◽  
pp. 771-779 ◽  
Author(s):  
Nicole L. Diggins ◽  
Donna J. Webb
Keyword(s):  
Signaling Pathways ◽  
Protein Interactions ◽  
Leucine Zipper ◽  
Adaptor Protein ◽  
Adaptor Proteins ◽  
Ph Domain ◽  
Protein Protein Interactions ◽  
Multiple Protein ◽  
Signaling Receptors ◽  
Ptb Domain

Endosomal adaptor proteins are important regulators of signaling pathways underlying many biological processes. These adaptors can integrate signals from multiple pathways via localization to specific endosomal compartments, as well as through multiple protein–protein interactions. One such adaptor protein that has been implicated in regulating signaling pathways is the adaptor protein containing a pleckstrin homology (PH) domain, phosphotyrosine-binding (PTB) domain, and leucine zipper motif 1 (APPL1). APPL1 localizes to a subset of Rab5-positive endosomes through its Bin–Amphiphysin–Rvs and PH domains, and it coordinates signaling pathways through its interaction with many signaling receptors and proteins through its PTB domain. This review discusses our current understanding of the role of APPL1 in signaling and trafficking, as well as highlights recent work into the function of APPL1 in cell migration and adhesion.

Adaptor protein containing PH domain, PTB domain and leucine zipper (APPL1) regulates the protein level of EGFR by modulating its trafficking

2011 ◽  
Vol 415 (1) ◽  
pp. 206-211 ◽  
Author(s):  
Jae-Rin Lee ◽  
Hwa-Sun Hahn ◽  
Young-Hoon Kim ◽  
Hong-Hoa Nguyen ◽  
Jun-Mo Yang ◽  
...  
Keyword(s):  
Protein Level ◽  
Leucine Zipper ◽  
Adaptor Protein ◽  
Ph Domain ◽  
Ptb Domain

scholarly journals SUN-687 MODY-14: A Rare Cause of Inherited Diabetes

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Riley Epp ◽  
Amel Arnaout ◽  
Mary-Anne Doyle
Keyword(s):  
Insulin Secretion ◽  
Leucine Zipper ◽  
Novel Mutation ◽  
Adaptor Protein ◽  
Alpha Helix ◽  
Ph Domain ◽  
Loss Of Function ◽  
Physically Active ◽  
Bar Domain ◽  
Oral Hypoglycemic Medications

Abstract Case: A 29-year-old physically active, lean man presented with a three-year history of poorly controlled diabetes diagnosed during a flu-like illness and no history diabetic ketoacidosis. Despite treatment with various oral hypoglycemic medications his glycated hemoglobin was consistently above target (never falling below 9.3%) and correlated with home blood glucose readings. His mother had gestational diabetes with all three of her pregnancies. His maternal grandmother was also known to have diabetes. Pancreatic islet antibodies were negative. C-peptide levels were low. Monogenic diabetes (MODY) was suspected. Discussion: Genetic testing revealed a mutation in the Adaptor Protein, Phosphotyrosine Interaction, PH domain, and leucine zipper containing 1 (APPL1) gene. APPL1 is involved in insulin secretion and insulin signaling via the Akt pathway [1,2,3]. Other mutations of APPL1 causing MODY-14 have been previously described [4]. In our case, the substitution of glutamate for aspartate at the 265 position occurs within the unique fourth alpha helix of the BAR domain of APPL1 [5]. Generally, BAR domains contribute to APPL1 dimerization and plasma membrane association [5]. Substitution of glutamate could disrupt protein folding, impairing dimerization and phosphorylation of Akt, thereby decreased insulin secretion as seen in other mutations of the BAR domain of APPL1 [4]. Although this remains a hypothesis, loss-of-function of APPL1 would explain the lack of insulin secretion without evidence of pancreatic autoimmunity. If the hypothesis is correct, it would be a novel mutation attributable to this MODY subtype. 1. Cheng KKY, Lam KSL, Wu D, et al. APPL1 potentiates insulin secretion in pancreatic β cells by enhancing protein kinase Akt-dependent expression of SNARE proteins in mice. Proc Natl Acad Sci U S A. 2012;109(23):8919–8924. doi:10.1073/pnas.1202435109 2. Ryu J, Galan AK, Xin X, et al. APPL1 potentiates insulin sensitivity by facilitating the binding of IRS1/2 to the insulin receptor. Cell Rep. 2014;7(4):1227–1238. doi:10.1016/j.celrep.2014.04.006 3. Saito T, Jones CC, Huang S, Czech MP, Pilch PF. The interaction of Akt with APPL1 is required for insulin-stimulated Glut4 translocation. J Biol Chem. 2007;282(44):32280–32287. doi:10.1074/jbc.M704150200 4. Prudente S, Jungtrakoon P, Marucci A, et al. Loss-of-Function Mutations in APPL1 in Familial Diabetes Mellitus. Am J Hum Genet. 2015;97(1):177–185. doi:10.1016/j.ajhg.2015.05.011 5. Li J, Mao X, Dong LQ, Liu F, Tong L. Crystal Structures of the BAR-PH and PTB Domains of Human APPL1. Structure. 2007;15(5):525–533. doi:10.1016/j.str.2007.03.011

scholarly journals Nck-2, a Novel Src Homology2/3-containing Adaptor Protein That Interacts with the LIM-only Protein PINCH and Components of Growth Factor Receptor Kinase-signaling Pathways

1998 ◽  
Vol 9 (12) ◽  
pp. 3367-3382 ◽  
Author(s):  
Yizeng Tu ◽  
Fugang Li ◽  
Chuanyue Wu
Keyword(s):  
Growth Factor ◽  
Signaling Pathways ◽  
Growth Factor Receptor ◽  
Adaptor Protein ◽  
Sh3 Domain ◽  
Sh2 Domain ◽  
Kinase Signaling ◽  
Egf Receptors ◽  
Growth Factor Receptor Signaling ◽  
Receptor Kinase Signaling

Many of the protein–protein interactions that are essential for eukaryotic intracellular signal transduction are mediated by protein binding modules including SH2, SH3, and LIM domains. Nck is a SH3- and SH2-containing adaptor protein implicated in coordinating various signaling pathways, including those of growth factor receptors and cell adhesion receptors. We report here the identification, cloning, and characterization of a widely expressed, Nck-related adaptor protein termed Nck-2. Nck-2 comprises primarily three N-terminal SH3 domains and one C-terminal SH2 domain. We show that Nck-2 interacts with PINCH, a LIM-only protein implicated in integrin-linked kinase signaling. The PINCH-Nck-2 interaction is mediated by the fourth LIM domain of PINCH and the third SH3 domain of Nck-2. Furthermore, we show that Nck-2 is capable of recognizing several key components of growth factor receptor kinase-signaling pathways including EGF receptors, PDGF receptor-β, and IRS-1. The association of Nck-2 with EGF receptors was regulated by EGF stimulation and involved largely the SH2 domain of Nck-2, although the SH3 domains of Nck-2 also contributed to the complex formation. The association of Nck-2 with PDGF receptor-β was dependent on PDGF activation and was mediated solely by the SH2 domain of Nck-2. Additionally, we have detected a stable association between Nck-2 and IRS-1 that was mediated primarily via the second and third SH3 domain of Nck-2. Thus, Nck-2 associates with PINCH and components of different growth factor receptor-signaling pathways via distinct mechanisms. Finally, we provide evidence indicating that a fraction of the Nck-2 and/or Nck-1 proteins are associated with the cytoskeleton. These results identify a novel Nck-related SH2- and SH3-domain–containing protein and suggest that it may function as an adaptor protein connecting the growth factor receptor-signaling pathways with the integrin-signaling pathways.

scholarly journals The Type Iα Inositol Polyphosphate 4-Phosphatase Generates and Terminates Phosphoinositide 3-Kinase Signals on Endosomes and the Plasma Membrane

2005 ◽  
Vol 16 (5) ◽  
pp. 2218-2233 ◽  
Author(s):  
Ivan Ivetac ◽  
Adam D. Munday ◽  
Marina V. Kisseleva ◽  
Xiang-Ming Zhang ◽  
Susan Luff ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Growth Factor ◽  
Effector Proteins ◽  
Type I ◽  
Endosomal Trafficking ◽  
Inositol Polyphosphate ◽  
Ph Domain ◽  
Membrane Recruitment ◽  
Early Endosomes ◽  
Phosphoinositide 3 Kinase

Endosomal trafficking is regulated by the recruitment of effector proteins to phosphatidylinositol 3-phosphate [PtdIns(3)P] on early endosomes. At the plasma membrane, phosphatidylinositol-(3,4)-bisphosphate [PtdIns(3,4)P2] binds the pleckstrin homology (PH) domain-containing proteins Akt and TAPP1. Type Iα inositol polyphosphate 4-phosphatase (4-phosphatase) dephosphorylates PtdIns(3,4)P2, forming PtdIns(3)P, but its subcellular localization is unknown. We report here in quiescent cells, the 4-phosphatase colocalized with early and recycling endosomes. On growth factor stimulation, 4-phosphatase endosomal localization persisted, but in addition the 4-phosphatase localized at the plasma membrane. Overexpression of the 4-phosphatase in serum-stimulated cells increased cellular PtdIns(3)P levels and prevented wortmannin-induced endosomal dilatation. Furthermore, mouse embryonic fibroblasts from homozygous Weeble mice, which have a mutation in the type I 4-phosphatase, exhibited dilated early endosomes. 4-Phosphatase translocation to the plasma membrane upon growth factor stimulation inhibited the recruitment of the TAPP1 PH domain. The 4-phosphatase contains C2 domains, which bound PtdIns(3,4)P2, and C2-domain-deletion mutants lost PtdIns(3,4)P2 4-phosphatase activity, did not localize to endosomes or inhibit TAPP1 PH domain membrane recruitment. The 4-phosphatase therefore both generates and terminates phosphoinositide 3-kinase signals at distinct subcellular locations.

scholarly journals The Arf6 GTPase-activating Proteins ARAP2 and ACAP1 Define Distinct Endosomal Compartments That Regulate Integrin α5β1 Traffic

2014 ◽  
Vol 289 (44) ◽  
pp. 30237-30248 ◽  
Author(s):  
Pei-Wen Chen ◽  
Ruibai Luo ◽  
Xiaoying Jian ◽  
Paul A. Randazzo
Keyword(s):  
Leucine Zipper ◽  
Focal Adhesions ◽  
Adaptor Protein ◽  
Ph Domain ◽  
Integrin Β1 ◽  
Recycling Endosome ◽  
Gtpase Activating Proteins ◽  
Cell Adhesion And Migration ◽  
And Migration ◽  
Opposing Effects

Arf6 and the Arf6 GTPase-activating protein (GAP) ACAP1 are established regulators of integrin traffic important to cell adhesion and migration. However, the function of Arf6 with ACAP1 cannot explain the range of Arf6 effects on integrin-based structures. We propose that Arf6 has different functions determined, in part, by the associated Arf GAP. We tested this idea by comparing the Arf6 GAPs ARAP2 and ACAP1. We found that ARAP2 and ACAP1 had opposing effects on apparent integrin β1 internalization. ARAP2 knockdown slowed, whereas ACAP1 knockdown accelerated, integrin β1 internalization. Integrin β1 association with adaptor protein containing a pleckstrin homology (PH) domain, phosphotyrosine-binding (PTB) domain, and leucine zipper motif (APPL)-positive endosomes and EEA1-positive endosomes was affected by ARAP2 knockdown and depended on ARAP2 GAP activity. ARAP2 formed a complex with APPL1 and colocalized with Arf6 and APPL in a compartment distinct from the Arf6/ACAP1 tubular recycling endosome. In addition, although ACAP1 and ARAP2 each colocalized with Arf6, they did not colocalize with each other and had opposing effects on focal adhesions (FAs). ARAP2 overexpression promoted large FAs, but ACAP1 overexpression reduced FAs. Taken together, the data support a model in which Arf6 has at least two sites of opposing action defined by distinct Arf6 GAPs.

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