Platelet-derived Growth Factor (PDGF) and PDGF Receptor Expression and Function in Folliculostellate Pituitary Cells

2009 ◽  
Vol 118 (02) ◽  
pp. 113-120 ◽  
Author(s):  
M. Kowarik ◽  
C. Onofri ◽  
T. Colaco ◽  
G. Stalla ◽  
U. Renner
Keyword(s):  
Growth Factor ◽  
Receptor Expression ◽  
Platelet Derived Growth Factor ◽  
Pituitary Cells ◽  
Pdgf Receptor ◽  
And Function

scholarly journals Induction of platelet-derived growth factor receptor expression in smooth muscle cells and fibroblasts upon tissue culturing.

1988 ◽  
Vol 107 (5) ◽  
pp. 1947-1957 ◽  
Author(s):  
L Terracio ◽  
L Rönnstrand ◽  
A Tingström ◽  
K Rubin ◽  
L Claesson-Welsh ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Smooth Muscle Cells ◽  
Human Skin ◽  
Muscle Cells ◽  
Receptor Expression ◽  
Platelet Derived Growth Factor ◽  
Pdgf Receptor ◽  
Myometrial Cells

The expression of platelet-derived growth factor (PDGF) receptors in porcine uterus and human skin in situ, was compared with that of cultured primary cells isolated from the same tissues. PDGF receptor expression was examined by monoclonal antibodies specific for the B type PDGF receptor and by RNA/RNA in situ hybridization with a probe constructed from a cDNA clone encoding the B type PDGF receptor. In porcine uterus tissue both mRNA and the protein product for the PDGF receptor were detected in the endometrium; the myometrium, in contrast, contained much lower amounts. Moreover, freshly isolated myometrial cells were devoid of PDGF receptors. However, after 1 d in culture receptors appeared, and after 2 wk of culturing essentially all of the myometrial cells stained positively with the anti-PDGF receptor antibodies and contained PDGF receptor mRNA. Similarly, B type PDGF receptors were not detected in normal human skin, but fibroblast-like cells from explant cultures of human skin possessed PDGF receptors. When determined by immunoblotting, porcine uterus myometrial membranes contained approximately 20% of the PDGF receptor antigen compared with the amount found in endometrial membranes. In addition, PDGF stimulated the phosphorylation of a 175-kD component, most likely representing autophosphorylation of the B type PDGF receptor in endometrial membranes, whereas only a marginal phosphorylation was seen in myometrial membranes. Taken together, these results demonstrate that PDGF receptor expression varies in normal tissues and that fibroblasts and smooth muscle cells do not uniformly express the receptor in situ. Furthermore, fibroblasts and smooth muscle cells that are released from tissues are induced to express PDGF receptors in response to cell culturing. The data suggest that, in addition to the availability of the ligand, PDGF-mediated cell growth in vivo is dependent on factors regulating expression of the receptor.

scholarly journals Down-regulation of cellular platelet-derived growth factor receptors induced by an activated neu receptor tyrosine kinase.

1991 ◽  
Vol 2 (8) ◽  
pp. 651-661 ◽  
Author(s):  
L Lehtola ◽  
M Nistér ◽  
E Hölttä ◽  
B Westermark ◽  
K Alitalo
Keyword(s):  
Growth Factor ◽  
Tyrosine Kinase ◽  
Receptor Expression ◽  
Platelet Derived Growth Factor ◽  
Target Cells ◽  
Mrna Levels ◽  
Pdgf Receptor ◽  
Down Regulation ◽  
Beta Receptors ◽  
Neu Oncogene

The functional integration of growth factor signaling occurs at several levels in target cells. One of the most proximal mechanisms is receptor transmodulation, by which one activated receptor can regulate the expression of other receptors in the same cells. Well-established transregulatory loops involve platelet-derived growth factor (PDGF) down-regulation of epidermal growth factor (EGF) receptors and beta-type transforming growth factors modulation of PDGF receptors. We have studied the relationship between neu tyrosine kinase activation and the expression of the PDGF receptors in transfected NIH/3T3 cells. Expression of the neu oncogene, but not of the neu proto-oncogene, was associated with a decrease of PDGF alpha- and beta-receptors on the cell surface, as measured by [125-I]PDGF-AA and -BB binding. These results were corroborated by metabolic labeling and immunoprecipitation of the PDGF beta-receptors. PDGF alpha- and beta-receptor mRNAs were strongly decreased in the neu oncogene-transformed cells in comparison with control cells expressing the neu proto-oncogene. Down-regulation of the PDGF receptors and their mRNAs was also observed after EGF treatment of cells expressing a chimeric EGF receptor/neu receptor, where the neu tyrosine kinase is activated by EGF binding. These results show that the neu tyrosine kinase can down-modulate PDGF receptor expression, and the effect is mediated via decreased PDGF receptor mRNA levels.

Calcium and growth responses of hyperresponsive airway smooth muscle to different isoforms of platelet-derived growth factor (PDGF)

2000 ◽  
Vol 78 (11) ◽  
pp. 867-873 ◽  
Author(s):  
Mary E Zacour ◽  
Barbara Tolloczko ◽  
James G Martin
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Intracellular Calcium ◽  
Airway Smooth Muscle ◽  
Receptor Expression ◽  
Platelet Derived Growth Factor ◽  
Pdgf Receptor ◽  
Growth Responses ◽  
Mitogenic Response ◽  
Pdgf Isoforms

Airway smooth muscle (ASM) mass is likely to be an important determinant of airway responsiveness. Highly inbred Fisher rats model innate hyperresponsiveness, and also have more ASM in vivo than control Lewis rats. Platelet derived growth factor (PDGF) is an important endogenous growth factor for ASM, and partially purified PDGF-AB causes enhanced growth of Fisher rat ASM cells, compared to Lewis cells. The aim of the present study was to determine the mitogenic effects of all three recombinant PDGF isoforms on ASM cells, and investigate the mechanisms of enhanced Fisher ASM growth responses. The potential mechanisms assessed include PDGF receptor expression and activation (tyrosine phoshorylation), and intracellular calcium (Ca2+) responses to PDGF isoforms. Fisher ASM cells had a greater mitogenic response to PDGF-AB and -AA, and a greater Ca2+ response to -BB than Lewis ASM cells. A Ca2+ response was not necessary for a mitogenic response, and the effects of PDGF isoforms on Ca2+ were not associated with their effects on growth. Therefore, we suggest that enhanced Fisher mitogenic response to PDGF-AA and -AB is not mediated by differences in Ca2+ signalling. Western analysis of the PDGF receptor indicated a similar expression of β-PDGF receptor in ASM cells from the two rat strains, but a greater expression of α-PDGF receptor in Fisher cells; however, phosphorylation of the PDGF receptor following growth stimulation did not differ between strains. This suggests a role for post-receptor signals, in addition to enhanced receptor expression, in the enhanced growth response of Fisher ASM cells to PDGF-AA and -AB.Key words: PDGF receptors, tyrosine phosphorylation, intracellular calcium, proliferation, airway smooth muscle cells.

scholarly journals Involvement of a phosphotyrosine protein phosphatase in the suppression of platelet-derived growth factor receptor autophosphorylation in ras-transformed cells

1993 ◽  
Vol 293 (1) ◽  
pp. 215-221 ◽  
Author(s):  
L Tomáska ◽  
R J Resnick
Keyword(s):  
Growth Factor ◽  
Phosphatase Activity ◽  
Receptor Tyrosine Kinase ◽  
Protein Phosphatase ◽  
Kinase Activity ◽  
Platelet Derived Growth Factor ◽  
Transformed Cells ◽  
Pdgf Receptor ◽  
Tyrosine Kinase Activity ◽  
Phosphotyrosine Protein Phosphatase

The nature of the suppression of platelet-derived growth factor (PDGF) receptor autophosphorylation in ras-transformed NIH 3T3 fibroblasts was investigated. The PDGF receptor from ras-transformed cells that had been purified by wheatgerm-lectin affinity chromatography displayed normal PDGF-induced autophosphorylation, indicating that the receptor is not irreversibly modified. Various phosphotyrosine-protein-phosphatase inhibitors did not reverse the inhibition of PDGF-receptor kinase in crude membrane preparations from ras-transformed cells. However, treatment of intact ras-transformed cells both with 2 mM sodium orthovanadate and with 20 microM phenylarsine oxide restored PDGF-receptor tyrosine-kinase activity to a level similar to that observed in normal cells. Direct measurement of the phosphatase activities in crude cellular fractions revealed a 2.5-fold higher membrane-associated phosphotyrosine-protein-phosphatase activity in ras-transformed cells, whereas phosphoserine-protein-phosphatase activity remained unchanged between the cell lines. These data suggest that the suppression of the PDGF-receptor tyrosine-kinase activity in ras-transformed cells is mediated via an inhibitory component, distinct from the receptor, that may be positively regulated by the dephosphorylation of tyrosine residue(s).

A small v-sis/platelet-derived growth factor (PDGF) B-protein domain in which subtle conformational changes abrogate PDGF receptor interaction and transforming activity

1990 ◽  
Vol 10 (10) ◽  
pp. 5496-5501
Author(s):  
N Giese ◽  
W J LaRochelle ◽  
M May-Siroff ◽  
K C Robbins ◽  
S A Aaronson
Keyword(s):  
Monoclonal Antibody ◽  
Growth Factor ◽  
Conformational Changes ◽  
Protein Domain ◽  
Platelet Derived Growth Factor ◽  
Receptor Interaction ◽  
Pdgf Receptor ◽  
Amino Acid Residues ◽  
Disulfide Linkages ◽  
Transforming Activity

Deletion scanning mutagenesis within the transforming region of the v-sis oncogene was used to dissect structure-function relationships. Mutations affecting codons within a domain encoding amino acids 136 through 148 had no effect upon homodimer formation or recognition by antisera which detect determinants dependent upon native intrachain disulfide linkages, yet the same mutations completely abolished transforming activity. A platelet-derived growth factor B (PDGF B) monoclonal antibody that prevents its interaction with PDGF receptors recognized v-sis, delta 142 (deletion of codon 142), and delta 148 but not delta 136, delta 137, or delta 139 mutants. These findings mapped the epitope recognized by this monoclonal antibody to include amino acid residues 136 to 139. Furthermore, mutations in the codon 136 to 148 domain caused markedly impaired ability to induce PDGF receptor tyrosine phosphorylation. Thus, subtle conformational alterations in this small domain critically affect PDGF receptor recognition and/or functional activation.

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