scholarly journals Healing of Gastrointestinal Mucosa: Involvement of Polyamines

Physiology ◽  
1999 ◽  
Vol 14 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Leonard R. Johnson ◽  
Shirley A. McCormack
Keyword(s):  
Signal Transduction ◽  
Cell Migration ◽  
Growth Factor ◽  
Egf Receptor ◽  
Receptor Function ◽  
Gastrointestinal Mucosa ◽  
Cellular Content ◽  
Mucosal Lesions ◽  
Signal Transduction Proteins ◽  
Cell Migration And Proliferation

Polyamines are involved in the processes of cell migration and proliferation that result in the repair of mucosal lesions. Depletion of polyamines dramatically alters the arrangement of the cytoskeleton, EGF receptor function, the activities of signal transduction proteins, the levels of several protooncogenes, and the expression and cellular content of at least one growth factor involved in these processes.

scholarly journals Integrins can collaborate with growth factors for phosphorylation of receptor tyrosine kinases and MAP kinase activation: roles of integrin aggregation and occupancy of receptors.

1996 ◽  
Vol 135 (6) ◽  
pp. 1633-1642 ◽  
Author(s):  
S Miyamoto ◽  
H Teramoto ◽  
J S Gutkind ◽  
K M Yamada
Keyword(s):  
Signal Transduction ◽  
Growth Factors ◽  
Growth Factor ◽  
Map Kinase ◽  
Tyrosine Kinases ◽  
Map Kinases ◽  
Egf Receptor ◽  
Growth Factor Receptor ◽  
Kinase Activation ◽  
Transient Activation

Integrins mediate cell adhesion, migration, and a variety of signal transduction events. These integrin actions can overlap or even synergize with those of growth factors. We examined for mechanisms of collaboration or synergy between integrins and growth factors involving MAP kinases, which regulate many cellular functions. In cooperation with integrins, the growth factors EGF, PDGF-BB, and basic FGF each produced a marked, transient activation of the ERK (extracellular signal-regulated kinase) class of MAP kinase, but only if the integrins were both aggregated and occupied by ligand. Transmembrane accumulation of total tyrosine-phosphorylated proteins, as well as nonsynergistic MAP kinase activation, could be induced by simple integrin aggregation, whereas enhanced transient accumulation of the EGF-receptor substrate eps8 required integrin aggregation and occupancy, as well as EGF treatment. Each type of growth factor receptor was itself induced to aggregate transiently by integrin ligand-coated beads in a process requiring both aggregation and occupancy of integrin receptors, but not the presence of growth factor ligand. Synergism was also observed between integrins and growth factors for triggering tyrosine phosphorylation of EGF, PDGF, and FGF receptors. This collaborative response also required both integrin aggregation and occupancy. These studies identify mechanisms in the signal transduction response to integrins and growth factors that require various combinations of integrin aggregation and ligands for integrin or growth factor receptors, providing opportunities for collaboration between these major regulatory systems.

Evidence for epidermal growth factor (EGF)-induced intermolecular autophosphorylation of the EGF receptors in living cells

1990 ◽  
Vol 10 (8) ◽  
pp. 4035-4044
Author(s):  
A M Honegger ◽  
A Schmidt ◽  
A Ullrich ◽  
J Schlessinger
Keyword(s):  
Signal Transduction ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Phosphorylation ◽  
Egf Receptor ◽  
Living Cells ◽  
Egf Receptors ◽  
Receptor Molecule ◽  
Epidermal Growth ◽  
Negative Mutant

In response to epidermal growth factor (EGF) stimulation, the intrinsic protein tyrosine kinase of EGF receptor is activated, leading to tyrosine phosphorylation of several cellular substrate proteins, including the EGF receptor molecule itself. To test the mechanism of EGF receptor autophosphorylation in living cells, we established transfected cell lines coexpressing a kinase-negative point mutant of EGF receptor (K721A) with an active EGF receptor mutant lacking 63 amino acids from its carboxy terminus. The addition of EGF to these cells caused tyrosine phosphorylation of the kinase-negative mutant by the active receptor molecule, demonstrating EGF receptor cross-phosphorylation in living cells. After internalization the kinase-negative mutant and CD63 have separate trafficking pathways. This limits their association and the extent of cross-phosphorylation of K721A by CD63. The coexpression of the kinase-negative mutant together with active EGF receptors in the same cells suppressed the mitogenic response toward EGF as compared with that in cells that express active receptors alone. The presence of the kinase-negative mutant functions as a negative dominant mutation suppressing the response of active EGF receptors, probably by interfering with EGF-induced signal transduction. It appears, therefore, that crucial events of signal transduction occur before K721A and active EGF receptors are separated by their different endocytic itineraries.

Cell migration and growth induced by photo-immobilised vascular endothelial growth factor (VEGF) isoforms

2019 ◽  
Vol 7 (27) ◽  
pp. 4272-4279 ◽  
Author(s):  
Xueli Ren ◽  
Jun Akimoto ◽  
Hideyuki Miyatake ◽  
Seiichi Tada ◽  
Liping Zhu ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Cell Migration ◽  
Growth Factor ◽  
Vascular Endothelial ◽  
Cell Migration And Proliferation ◽  
Endothelial Growth Factor ◽  
Vegf Isoforms

VEGF isoforms immobilised by photo-reactive gelatin (AzPhe-gelatin) enhance cell migration and proliferation.

scholarly journals Signal transduction by epidermal growth factor and heregulin via the kinase-deficient ErbB3 protein

1998 ◽  
Vol 334 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Hong-Hee KIM ◽  
Ulka VIJAPURKAR ◽  
Nathan J. HELLYER ◽  
Dolores BRAVO ◽  
John G. KOLAND
Keyword(s):  
Signal Transduction ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Protein Tyrosine Kinase ◽  
Kinase Activity ◽  
Egf Receptor ◽  
Tyrosine Kinase Activity ◽  
Epidermal Growth ◽  
Protein Tyrosine Kinase Activity

The role of protein tyrosine kinase activity in ErbB3-mediated signal transduction was investigated. ErbB3 was phosphorylated in vivo in response to either heregulin (HRG) in cells expressing both ErbB3 and ErbB2, or epidermal growth factor (EGF) in cells expressing both ErbB3 and EGF receptor. A recombinant receptor protein (ErbB3-K/M, in which K/M stands for Lys → Met amino acid substitution) containing an inactivating mutation in the putative ATP-binding site was also phosphorylated in response to HRG and EGF. Both the wild-type ErbB3 and mutant ErbB3-K/M proteins transduced signals to phosphatidylinositol 3-kinase, Shc and mitogen-activated protein kinases. Separate kinase-inactivating mutations in the EGF receptor and ErbB2 proteins abolished ErbB3 phosphorylation and signal transduction activated by EGF and HRG respectively. Hence the protein tyrosine kinase activity necessary for growth factor signalling via the ErbB3 protein seems to be provided by coexpressed EGF and ErbB2 receptor proteins.

RLIP76, an effector of the GTPase Ral, interacts with the AP2 complex: involvement of the Ral pathway in receptor endocytosis

2000 ◽  
Vol 113 (16) ◽  
pp. 2837-2844 ◽  
Author(s):  
V. Jullien-Flores ◽  
Y. Mahe ◽  
G. Mirey ◽  
C. Leprince ◽  
B. Meunier-Bisceuil ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Growth Factor ◽  
Egf Receptor ◽  
The Other ◽  
Ras Signaling ◽  
Receptor Endocytosis ◽  
Epidermal Growth ◽  
Two Hybrid

RLIP76 is a modular protein that was identified as a putative effector of Ral, a GTPase activated during Ras signaling. To explore further the contribution of the Ral-RLIP76 pathway to Ras signaling, we have looked for partners of RLIP76. Mu2, the medium chain of the AP2 complex is shown to interact with RLIP76. We show also that in vivo endogenous AP2 and RLIP76 form a complex and that this in vivo interaction is independent of cells being stimulated by a growth factor. Furthermore, RLIP76 differentiates AP2 from AP1 in vivo as RLIP76 differentiates mu2 from mu1 in vitro and in two hybrid assays. We show that activated Ral interferes with both tranferrin receptor endocytosis and epidermal growth factor (EGF) receptor endocytosis in HeLa cells. We propose a model where the Ral-RLIP76 pathway connects signal transduction and endocytosis through interaction on one hand between the Ras-Ral pathway and RLIP, on the other hand between RLIP and proteins belonging to the endocytotic machinery.

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