scholarly journals Transforming growth factor alpha: mutation of aspartic acid 47 and leucine 48 results in different biological activities.

1988 ◽  
Vol 8 (3) ◽  
pp. 1247-1252 ◽  
Author(s):  
E Lazar ◽  
S Watanabe ◽  
S Dalton ◽  
M B Sporn
Keyword(s):  
Amino Acids ◽  
Biological Activity ◽  
Amino Acid ◽  
Growth Factor ◽  
Aspartic Acid ◽  
Transforming Growth Factor ◽  
Biologically Active ◽  
Single Amino Acid ◽  
Transforming Growth Factor Alpha ◽  
Factor Alpha

To study the relationship between the primary structure of transforming growth factor alpha (TGF-alpha) and some of its functional properties (competition with epidermal growth factor (EGF) for binding to the EGF receptor and induction of anchorage-independent growth), we introduced single amino acid mutations into the sequence for the fully processed, 50-amino-acid human TGF-alpha. The wild-type and mutant proteins were expressed in a vector by using a yeast alpha mating pheromone promoter. Mutations of two amino acids that are conserved in the family of the EGF-like peptides and are located in the carboxy-terminal part of TGF-alpha resulted in different biological effects. When aspartic acid 47 was mutated to alanine or asparagine, biological activity was retained; in contrast, substitutions of this residue with serine or glutamic acid generated mutants with reduced binding and colony-forming capacities. When leucine 48 was mutated to alanine, a complete loss of binding and colony-forming abilities resulted; mutation of leucine 48 to isoleucine or methionine resulted in very low activities. Our data suggest that these two adjacent conserved amino acids in positions 47 and 48 play different roles in defining the structure and/or biological activity of TGF-alpha and that the carboxy terminus of TGF-alpha is involved in interactions with cellular TGF-alpha receptors. The side chain of leucine 48 appears to be crucial either indirectly in determining the biologically active conformation of TGF-alpha or directly in the molecular recognition of TGF-alpha by its receptor.

Transforming growth factor alpha: mutation of aspartic acid 47 and leucine 48 results in different biological activities

1988 ◽  
Vol 8 (3) ◽  
pp. 1247-1252
Author(s):  
E Lazar ◽  
S Watanabe ◽  
S Dalton ◽  
M B Sporn
Keyword(s):  
Amino Acids ◽  
Biological Activity ◽  
Amino Acid ◽  
Growth Factor ◽  
Aspartic Acid ◽  
Transforming Growth Factor ◽  
Biologically Active ◽  
Single Amino Acid ◽  
Transforming Growth Factor Alpha ◽  
Factor Alpha

To study the relationship between the primary structure of transforming growth factor alpha (TGF-alpha) and some of its functional properties (competition with epidermal growth factor (EGF) for binding to the EGF receptor and induction of anchorage-independent growth), we introduced single amino acid mutations into the sequence for the fully processed, 50-amino-acid human TGF-alpha. The wild-type and mutant proteins were expressed in a vector by using a yeast alpha mating pheromone promoter. Mutations of two amino acids that are conserved in the family of the EGF-like peptides and are located in the carboxy-terminal part of TGF-alpha resulted in different biological effects. When aspartic acid 47 was mutated to alanine or asparagine, biological activity was retained; in contrast, substitutions of this residue with serine or glutamic acid generated mutants with reduced binding and colony-forming capacities. When leucine 48 was mutated to alanine, a complete loss of binding and colony-forming abilities resulted; mutation of leucine 48 to isoleucine or methionine resulted in very low activities. Our data suggest that these two adjacent conserved amino acids in positions 47 and 48 play different roles in defining the structure and/or biological activity of TGF-alpha and that the carboxy terminus of TGF-alpha is involved in interactions with cellular TGF-alpha receptors. The side chain of leucine 48 appears to be crucial either indirectly in determining the biologically active conformation of TGF-alpha or directly in the molecular recognition of TGF-alpha by its receptor.

scholarly journals Substitution of lysine for arginine at position 42 of human transforming growth factor-alpha eliminates biological activity without changing internal disulfide bonds.

1989 ◽  
Vol 9 (9) ◽  
pp. 4083-4086 ◽  
Author(s):  
D Defeo-Jones ◽  
J Y Tai ◽  
G A Vuocolo ◽  
R J Wegrzyn ◽  
T L Schofield ◽  
...  
Keyword(s):  
Biological Activity ◽  
Growth Factor ◽  
Receptor Binding ◽  
Disulfide Bonds ◽  
Egf Receptor ◽  
Transforming Growth Factor ◽  
Receptor Interaction ◽  
Composition Analysis ◽  
Transforming Growth Factor Alpha ◽  
Factor Alpha

Transforming growth factor-alpha (TGF-alpha) is a growth-promoting protein that binds to the epidermal growth factor (EGF) receptor. To identify critical residues that govern TGF-alpha-EGF receptor binding, we prepared site-specific substitution mutants of TGF-alpha. Mutant proteins were tested in receptor-binding and mitogenesis assays. Semiconservative substitutions at positions 4, 12, 18, and 45 decreased biological activity 2.1- to 14-fold. The conservative substitution of lysine for arginine at position 42 completely eliminated biological activity. Amino acid composition analysis of proteolytic fragments from TGF-alpha and the Lys-42 mutant indicated that these proteins contained the same disulfide bonds. These studies suggest that arginine 42 may be a contact point for TGF-alpha-EGF receptor interaction.

Transforming growth factor alpha: an aromatic side chain at position 38 is essential for biological activity

1989 ◽  
Vol 9 (2) ◽  
pp. 860-864
Author(s):  
E Lazar ◽  
E Vicenzi ◽  
E Van Obberghen-Schilling ◽  
B Wolff ◽  
S Dalton ◽  
...  
Keyword(s):  
Biological Activity ◽  
Growth Factor ◽  
Disulfide Bonds ◽  
Transforming Growth Factor ◽  
Site Directed Mutagenesis ◽  
Side Chain ◽  
Transforming Growth Factor Alpha ◽  
Aromatic Side Chain ◽  
Factor Alpha ◽  
Alpha Gene

Site-directed mutagenesis has been performed in the human transforming growth factor alpha gene. When tyrosine 38 is mutated into phenylalanine or tryptophane, biological activity is retained. In contrast, other alterations between cysteine 34 and cysteine 43 and disruption of disulfide bonds 8 to 21 and 34 to 43 resulted in loss of activities. The presence of an aromatic side chain at position 38 of transforming growth factor alpha seems to be essential for its activity.

scholarly journals Expression and characterization of transforming growth factor alpha precursor protein in transfected mammalian cells.

1987 ◽  
Vol 7 (5) ◽  
pp. 1585-1591 ◽  
Author(s):  
L E Gentry ◽  
D R Twardzik ◽  
G J Lim ◽  
J E Ranchalis ◽  
D C Lee
Keyword(s):  
Amino Acid ◽  
Growth Factor ◽  
Mammalian Cells ◽  
Transforming Growth Factor ◽  
Precursor Protein ◽  
Transforming Growth Factor Alpha ◽  
Cell Fractionation ◽  
Precursor Molecule ◽  
Bhk Cells ◽  
Factor Alpha

Analysis of a cDNA clone derived from retrovirus-transformed rat fibroblasts has recently suggested that the mature 50-amino-acid form of transforming growth factor alpha (TGF alpha) is derived from a 159-amino-acid transmembrane precursor by proteolytic cleavage. To understand the processing of the TGF alpha precursor molecule in more detail, we have expressed this protein in baby hamster kidney (BHK) fibroblasts under control of the metal-ion-inducible metallothionein promoter and characterized the expressed precursor with site-specific antipeptide antibodies. One of the BHK transfectants, termed 5:2, expressed the TGF alpha mRNA in a cadmium- and zinc-inducible manner. The TGF alpha precursor protein was detected by immunoprecipitation analysis of radiolabeled cell cultures. In the induced 5:2 cells, a polypeptide of Mr 13,000 to 17,000 was readily identified by peptide antisera made to three different regions of the TGF alpha precursor protein. No such protein species were observed in BHK cells treated with cadmium and zinc or in uninduced 5:2 cells. However, two cell lines known to produce TGF alpha naturally, Leydig testicular tumor cells and Snyder-Theilan feline sarcoma virus-transformed Fisher rat embryo fibroblasts, possessed detectable levels of immunologically related Mr 13,000 to 17,000 proteins. Cell fractionation studies indicate that the Mr 13,000 to 17,000 species expressed in induced 5:2 cells is membrane associated, consistent with predictions based on the cDNA sequence of the TGF alpha precursor. Media conditioned by induced 5:2 cells contained epidermal growth factor receptor-competing activity, which, upon size fractionation, was similar in size to the mature processed form of TGF alpha. These data show that these nontransformed BHK cells possess the ability to process the TGF alpha precursor molecule into its native form.

Assessment of biological activity of synthetic fragments of transforming growth factor-alpha

1988 ◽  
Vol 36 (4) ◽  
pp. 341-352 ◽  
Author(s):  
Krzysztof Darlak ◽  
Glen Franklin ◽  
Philip Woost ◽  
Elaine Sonnenfeld ◽  
Daniel Twardzik ◽  
...  
Keyword(s):  
Biological Activity ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Alpha ◽  
Factor Alpha

scholarly journals Transforming growth factor alpha: an aromatic side chain at position 38 is essential for biological activity.

1989 ◽  
Vol 9 (2) ◽  
pp. 860-864 ◽  
Author(s):  
E Lazar ◽  
E Vicenzi ◽  
E Van Obberghen-Schilling ◽  
B Wolff ◽  
S Dalton ◽  
...  
Keyword(s):  
Biological Activity ◽  
Growth Factor ◽  
Disulfide Bonds ◽  
Transforming Growth Factor ◽  
Site Directed Mutagenesis ◽  
Side Chain ◽  
Transforming Growth Factor Alpha ◽  
Aromatic Side Chain ◽  
Factor Alpha ◽  
Alpha Gene

Site-directed mutagenesis has been performed in the human transforming growth factor alpha gene. When tyrosine 38 is mutated into phenylalanine or tryptophane, biological activity is retained. In contrast, other alterations between cysteine 34 and cysteine 43 and disruption of disulfide bonds 8 to 21 and 34 to 43 resulted in loss of activities. The presence of an aromatic side chain at position 38 of transforming growth factor alpha seems to be essential for its activity.

Biological activity of a transforming growth factor-alpha-Pseudomonas exotoxin fusion protein in vitro and in vivo

1991 ◽  
Vol 7 (3) ◽  
pp. 203-207 ◽  
Author(s):  
David C. Heimbrook ◽  
Steven M. Stirdivant ◽  
Janet D. Ahern ◽  
Nancy L. Balishin ◽  
Denis R. Patrick ◽  
...  
Keyword(s):  
Biological Activity ◽  
Growth Factor ◽  
Fusion Protein ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Alpha ◽  
Pseudomonas Exotoxin ◽  
Factor Alpha

Structure-function analysis of synthetic and recombinant derivatives of transforming growth factor alpha

1988 ◽  
Vol 8 (8) ◽  
pp. 2999-3007
Author(s):  
D Defeo-Jones ◽  
J Y Tai ◽  
R J Wegrzyn ◽  
G A Vuocolo ◽  
A E Baker ◽  
...  
Keyword(s):  
Amino Acid ◽  
Growth Factor ◽  
Receptor Binding ◽  
Transforming Growth Factor ◽  
Function Analysis ◽  
Mitogenic Activity ◽  
Transforming Growth Factor Alpha ◽  
Mutant Proteins ◽  
Biologic Activity ◽  
Factor Alpha

Transforming growth factor alpha (TGF-alpha) is a 50-amino-acid peptide that stimulates cell proliferation via binding to cell surface receptors. To identify the structural features of TGF-alpha that govern receptor-ligand interactions, we prepared synthetic peptide fragments and recombinant mutant proteins of TGF-alpha. These TGF-alpha derivatives were tested in receptor binding and mitogenesis assays. Synthetic peptides representing the N terminus, the C terminus, or the individual disulfide constrained rings of TGF-alpha did not exhibit receptor-binding or mitogenic activity. Replacement of the cysteines with alanines at positions 8 and 21, 16 and 32, and 34 and 43 or at positions 8 and 21 and 34 and 43 yielded inactive mutant proteins. However, mutant proteins containing substitutions or deletions in the N-terminal region retained significant biologic activity. Conservative amino acid changes at residue 29 or 38 or both and a nonconservative amino acid change at residue 12 had little effect on binding or mitogenesis. However, nonconservative amino acid changes at residues 15, 38, and 47 produced dramatic decreases in receptor binding (23- to 71-fold) and mitogenic activity (38- to 125-fold). These studies indicate that at least three distinct regions of TGF-alpha contribute to biologic activity.

Sign in / Sign up

Export Citation Format

Share Document