• D) Western blot showing the immunoprecipitation (left) and total (right) protein levels of E-cad, Pkp3, Rap1, and EPAC for indicated conditions. (nih.gov)
  • Note that E-cad loss does not interfere with the interaction between Pkp3, Rap1, and EPAC. (nih.gov)
  • Note that the EPAC inhibitor ESI-09 causes the loss of E-cad but not Pkp3 from the Rap1 complex. (nih.gov)
  • E-cad knockdown did not have the same disruptive effect on Pkp3-Rap1 interaction or the interaction between Rap1 and its main activator, EPAC, suggesting that Pkp3 is required for Rap1 interaction with E-cad, but E-cad is not required for Pkp3-Rap1 interaction (Figure 7D). (nih.gov)
  • To test whether the activity of the Rap1 GEF EPAC was required for the maintenance of a Rap1/Pkp3/E-cad complex, we inhibited EPAC activity by using its well-established chemical inhibitor ESI-09 (Almahariq et al. (nih.gov)
  • 2013). In the absence of EPAC activity, E-cad is excluded from a complex that still contains Pkp3 and Rap1, supporting the idea that Pkp3 provides a scaffold for binding and activation of Rap1 required for E-cad association (Figure 7E). (nih.gov)
  • EPAC1 and EPAC2, two isoforms of exchange proteins directly activated by cAMP (EPAC), respond to the second messenger cAMP and regulate a wide variety of intracellular processes under physiological and pathophysiological circumstances. (pubmedcentralcanada.ca)
  • However, the contribution of more recently discovered cAMP target exchange proteins directly activated by cAMP (EPAC) is becoming more and more appreciated. (pubmedcentralcanada.ca)
  • 8 - 10 Therefore, advances in the understanding the role of EPAC proteins as regulators of cAMP-dependent signaling are critical for further elucidating the mechanism of cAMP signaling. (pubmedcentralcanada.ca)
  • The signaling module cAMP/Epac/Rap1/PLCε/IP3 mobilizes acrosomal calcium during sperm exocytosis. (nih.gov)
  • Last, we present direct evidence that cAMP, Epac, Rap1, and PLCε are necessary for calcium mobilization from sperm's secretory granule. (nih.gov)
  • In this study, we show that activation of Epac or Rap1 leads to potent inhibition of angiogenesis in vivo. (nih.gov)
  • Blockade of TSP1 binding to its receptor, CD36, rescues inhibition of chemotaxis or angiogenesis by activated Epac/Rap1. (nih.gov)
  • Finally, TSP1 is also secreted by fibroblasts in response to Epac/Rap1 activation. (nih.gov)
  • These results identify Epac and Rap1 as inhibitory regulators of the angiogenic process, implicate Id1 and TSP1 as downstream mediators of Epac/Rap1, and highlight a novel interplay between pro- and antiangiogenic signaling cascades involving multiple cell types within the angiogenic microenvironment. (nih.gov)
  • RAPL is also an integrin-associated protein as RAPL polarizes to the immunological synapse following antigen stimulation of T cells, colocalizes with LFA-1 following TCR or chemokine stimulation, and co-immunoprecipitates with LFA-1 in a Rap1-dependent manner (108). (wikipedia.org)
  • This provides a mechanism by which Rap1 can act directly on integrins and modulate integrin affinity and/or clustering. (wikipedia.org)
  • Thus, PKD may play a distinct role in regulating Rap1-dependent integrin regulation. (wikipedia.org)
  • In addition, if VAV2 is artificially localized to the cell edge with the subcellular targeting domain of Rap1a, it increases cell spreading independently of Rap1. (nih.gov)
  • The absence of 17N Rap1a at the cell periphery conflicted with our pseudopodia fractionation studies and could be a secondary effect due to the lack of membrane protrusions around the circumference of cells in which Rap1 is inhibited. (nih.gov)
  • Accordingly, the Rac GEF SWAP-70, which induces cell spreading independently of Rap1, was expressed with 63E or 17N Rap1a. (nih.gov)
  • Consistent with the pseudopodia fractionation results (Fig. 6), both 63E Rap1a and 17N Rap1a were enriched in circumferential protrusions in SWAP-70-expressing cells (Fig. 7 A). These data suggest that both active and inactive Rap1 localize to Rac-dependent membrane protrusions. (nih.gov)
  • In SP thymocytes, deficiency of Mst1 and Mst2 abolished sphingosine-1 phosphate- and CCL21-induced Mob1 phosphorylation, Rac1 and RhoA GTP charging, and subsequent cell migration. (rupress.org)
  • It is on the C-terminal tail that the various conserved protein binding motifs and phosphorylation sites of GAB2 are found. (wikipedia.org)
  • moreover, TNF-α can elevate MAP4K4 expression using transcription factors The JNK pathway is implicated in a number of physiological processes and involves JNKs - kinases responsible for the phosphorylation of a downstream protein called c-Jun. (wikipedia.org)
  • Play media Nucleotide exchange factors (NEFs) are proteins that stimulate the exchange (replacement) of nucleoside diphosphates for nucleoside triphosphates bound to other proteins. (wikipedia.org)
  • DOCK family proteins are inefficient at promoting nucleotide exchange on their own since they appear to adopt an autoinhibitory conformation in their resting state. (wikipedia.org)
  • Instead they possess a DHR2 domain which mediates G protein activation by stabilising it in its nucleotide free state. (wikipedia.org)
  • It functions as a diacylglycerol (DAG)-regulated nucleotide exchange factor specifically activating Ras through the exchange of bound GDP for GTP. (wikipedia.org)
  • More recently, Rap1 has been shown to play a role in cell adhesion, specifically in the positioning of adherens junctions in proliferating epithelial cells ( K nox and B rown 2002 ). (genetics.org)
  • As a second test for VAV2 localization, we examined the subcellular distribution of Rap1 and VAV2 in spreading cells using immunofluorescence (Fig. 7). (nih.gov)
  • A striking feature of Rap1 and the Rap1-associated signaling proteins PKD, RAPL, and Mst1 is their localization to membranes where integrins are found. (wikipedia.org)
  • Two other groups later cloned GAB2 by searching DNA database for protein with sequence homology to GAB1. (wikipedia.org)
  • Although Rap1 and RAPL have been shown to regulate both LFA-1 affinity and clustering, overexpression of Mst1 only enhances LFA-1 clustering. (wikipedia.org)
  • TNF-induced activation of both NF-κB and JNK requires TNF receptor-associated factor 2 (TRAF2) ( 12 - 16 ), a member of the TRAF family of proteins that associate with and transduce signals from TNF receptor family members ( 12 , 17 - 28 ). (pnas.org)
  • The N-terminal is characterized by a Pleckstrin Homology (PH) domain that is the most highly conserved region between all members of the GAB family of proteins. (wikipedia.org)
  • Many cellular proteins cleave (hydrolyze) nucleoside triphosphates-adenosine triphosphate (ATP) or guanosine triphosphate (GTP)-to their diphosphate forms (ADP and GDP) as a source of energy and to drive conformational changes. (wikipedia.org)
  • In their resting state G proteins are bound to Guanosine diphosphate (GDP) and their activation requires the dissociation of GDP and binding of guanosine triphosphate (GTP). (wikipedia.org)
  • M-Ras shares a similar structure with H-Ras and Rap2A with the exception of its switch 1 conformation when bound to guanosine 5'-(beta,gamma-imido)triphosphate (Gpp(NH)p). (wikipedia.org)
  • 100 small G proteins have been identified in eukaryotes from yeast to humans. (ahajournals.org)
  • 5-8 Importantly, recent accumulating evidence highlighted the significance of these small G proteins as essential molecular switches that trigger many of the signal transduction and functions of Ang II. (ahajournals.org)
  • In this review, we describe detailed mechanisms of signal transduction pathways of Ang II involving small G proteins in VSMCs together with their functional significances in mediating vascular remodeling. (ahajournals.org)
  • Activated by virtually all receptor types and second messengers, Rap1 controls adhesion-related functions such as phagocytosis, cell-cell contacts and functional activation of integrins through inside-out signalling. (biologists.org)
  • The TRAF domain is involved in receptor association and homo- and hetero-oligomerization of TRAFs and serves as a docking site for a number of other signaling proteins ( 13 , 17 - 19 , 29 - 34 ). (pnas.org)
  • Earlier studies have shown that megakaryoblastic cell lines express the prostacyclin receptor 5 Rap1 6 and the 97-kDa sarco/endoplasmic reticulum Ca 2+ -ATPase SERCA3b, which functions in Ca 2+ sequestration in platelets. (ahajournals.org)
  • It is hypothesized that binding sites in this region may be used in indirect mechanisms pairing the GAB2 protein to receptor tyrosine kinases. (wikipedia.org)
  • GAB2 mediates the interactions between receptor tyrosine kinases (RTK) or non-RTK receptors, such as G protein coupled receptors, cytokine receptors, multichain immune recognition receptors and integrins, and the molecules of the intracellular signaling pathways. (wikipedia.org)
  • Further, Rap1 activation appears to be stimulated by numerous exchange factors that do not act on the prototypic Ras GTPases. (genetics.org)
  • TNF triggers the activation of two transcription factors, nuclear factor-κB (NF-κB) ( 5 ) and activator protein 1 (AP-1) ( 6 ), which regulate the expression of numerous immune and inflammatory response genes (for reviews see, refs. (pnas.org)
  • Of the six described TRAF proteins, TRAF5 and TRAF6 have also been implicated in NF-κB activation. (pnas.org)
  • Consistent with coupling of transcription to the nuclear pore, we show that transcriptional activation of the GAL genes results in their association with nuclear pore proteins, relocation to the nuclear periphery, and loss of RanGEF association. (nih.gov)
  • In vitro binding studies showed that Rap1p binds to the 18 bp element essential for transcriptional activation. (nih.gov)
  • While lysines 1097 and 1099 are critical for Rap1-dependent activation of LFA-1, the β2-subunit cytoplasmic domain appears to be dispensable for activation of LFA-1 by Rap1 (126). (wikipedia.org)
  • Mutation of these lysine residues to alanine impairs the ability of LFA-1 to redistribute to the leading edge induced by Rap1 activation or overexpression of RAPL. (wikipedia.org)
  • M-Ras is involved in TNF-alpha-stimulated and Rap1-mediated LFA-1 activation in splenocytes. (wikipedia.org)
  • By binding to the p85 subunit of PI3K, and continuing this signaling pathway GAB provides positive feedback for the creation of PIP3, produced as a result of the PI3K pathway, which binds to GAB2 in the membrane and promotes activation of more PI3Ks. (wikipedia.org)
  • Identification and development of small-molecule probes with high potency and specificity represents a major effort for chemical biologists to explore and validate the roles of the proteins in a broader biological context. (pubmedcentralcanada.ca)
  • Rap1 plays a dominant role in the control of cell-cell and cell-matrix interactions by regulating the function of integrins and other adhesion molecules in various cell types. (genome.jp)
  • This finding suggests that LFA-1 clustering is critical for TCR signaling to integrins that is mediated by Rap1. (wikipedia.org)
  • The figure illustrates competition among three prominent membrane proteins (TARP, LRRTM, and neuroligin) and cytosolic synGAP-α1. (nih.gov)
  • 6 The data show that in addition to MEG-01 cells, human stem cells and immature megakaryocytes respond to iloprost with an increase in cAMP and a rise in [Ca 2+ ] i and that cAMP controls cytosolic Ca 2+ , possibly via Rap1-GTP. (ahajournals.org)
  • We also describe a central role for mitogen-activated protein kinases in controlling chromatin signaling in plasticity and memory. (nih.gov)
  • But unlike PKC, the C1 domains of Raf family kinases do not bind diacylglycerol. (wikipedia.org)