Selection and Characterization of Small Random Transmembrane Proteins that Bind and Activate the Platelet-derived Growth Factor β Receptor

Freeman-Cook, Lisa L.; Dixon, Ann M.; Frank, Jennifer B.; Xia, Yu; Ely, Lara; Gerstein, Mark; Engelman, Donald M.; DiMaio, Daniel

doi:10.1016/j.jmb.2004.03.044

Cited by 54 publications

(77 citation statements)

References 49 publications

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“…In a remarkable series of experiments involving growth factor recep- tors, two sets of investigators have found that peptide segments corresponding to their intramembranous domains were able to alter the activities of the cognate receptors. Small hydrophobic peptides were able to either induce dimer formation in the case of the platelet-derived growth factor receptor (35) or inhibit dimerization of the Erb B receptor (36), and both were believed to act by associating with the corresponding intramembranous domains of the transmembrane molecules.…”

Section: Discussionmentioning

confidence: 99%

An alternative interpretation of the amyloid Aβ hypothesis with regard to the pathogenesis of Alzheimer's disease

Marchesi

2005

Proc. Natl. Acad. Sci. U.S.A.

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Alzheimer's disease is a complex neurodegenerative process that is believed to be due to the accumulation of short, hydrophobic peptides derived from amyloid precursor proteins by proteolytic cleavage. It is widely believed that these A␤ peptides are secreted into the extracellular spaces of the CNS, where they assemble into toxic oligomers that kill neurons and eventually form deposits of senile plaques. This essay explores the possibility that a fraction of these A␤ peptides never leave the membrane lipid bilayer after they are generated, but instead exert their toxic effects by competing with and compromising the functions of intramembranous segments of membrane-bound proteins that serve many critical functions. Based on the presence of shared amino acid sequences containing GxxG motifs, I speculate that accumulations of intramembranous A␤ peptides might affect the functions of amyloid precursor protein itself and the assembly of the PS1, Aph1, Pen 2, Nicastrin complex.

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Section: Discussionmentioning

confidence: 99%

An alternative interpretation of the amyloid Aβ hypothesis with regard to the pathogenesis of Alzheimer's disease

Marchesi

2005

Proc. Natl. Acad. Sci. U.S.A.

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“…C127, CV1, and 293T cells were maintained as described (23). Retroviral stocks pseudotyped with VSV G protein were prepared in 293T cells and concentrated (see SI Text).…”

Section: Methodsmentioning

confidence: 99%

“…We generated libraries encoding many different small proteins in which the central segment of the E5 protein was replaced with random sequences of predominantly hydrophobic amino acids (23,24). Small TM proteins that induced focus formation in murine C127 fibroblasts were selected from these libraries and characterized.…”

mentioning

confidence: 99%

“…Small TM proteins that induced focus formation in murine C127 fibroblasts were selected from these libraries and characterized. In libraries containing the hydrophilic residues important for the E5-PDGF␤R interaction, Ϸ10% of the clones induced focus formation (23), demonstrating that many different TM sequences permitted cell transformation if essential hydrophilic interactions were retained. All of the active small TM proteins recovered from the libraries transformed cells by activating the PDGF␤R via interactions involving the TM domain of the receptor.…”

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confidence: 99%

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Packing contacts can mediate highly specific interactions between artificial transmembrane proteins and the PDGFβ receptor

Ptacek¹,

Edwards²,

Freeman-Cook³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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We used proteins with randomized transmembrane (TM) domains to explore the role of hydrophobic amino acids in mediating specific interactions between transmembrane helices. The 44-aa bovine papillomavirus E5 protein, which binds to the TM domain of the PDGF␤ receptor (PDGF␤R) was used as a scaffold to construct a library encoding small dimeric proteins with randomized, strictly hydrophobic TM domains, and proteins were selected that induced focus formation in mouse C127 cells by activating the PDGF␤R. Analysis of these proteins identified a motif of two hydrophobic residues that, when inserted into a 17-residue polyleucine TM domain, generated a protein that activated the PDGF␤R and transformed cells. In addition, we identified transforming proteins that activated the wild-type PDGF␤R but did not activate a series of PDGF␤R TM point mutants that were efficiently activated by the E5 protein, indicating that these proteins were more specific than the E5 protein. Our results implied that multiple van der Waals interactions distributed along the entire length of the TM domains were required for productive interaction between the PDGF␤R and some small proteins lacking hydrophilic TM residues. Our results also suggested that excluding hydrophilic residues from small TM proteins and peptides is a strategy to increase the specificity of heteromeric TM helix-helix interactions.helix interactions ͉ receptor activation ͉ ES protein M any essential cellular processes require proteins that are anchored in cell membranes. Most membrane-spanning domains cross membranes as ␣-helices, which can engage in highly specific side-by-side interactions with one another (1, 2). Transmembrane (TM) helix-helix interactions can mediate oligomerization of TM proteins, control their activity, and assist the proper folding of multipass TM proteins. Thus, understanding the basis for specific interactions between TM helices will provide considerable insight into the structure and function of cellular TM proteins.Detailed analysis of homodimerization of the TM domain of the major red blood cell protein, glycophorin A, suggested that the precise geometry of van der Waals interactions between hydrophobic side-chains is a major determinant of specificity and identified a GlyXXXGly motif important for dimer formation (3-5). Leucine zippers or multiple serine and threonine residues can also drive homodimer formation (6, 7). Studies with hydrophobic peptides and TM proteins showed that hydrogen bonding or charge-charge interactions between strongly polar residues can induce the formation of homooligomers and to a large extent obviate the requirement for specific packing interactions between hydrophobic side-chains (8-11). Strong interactions between hydrophilic side-chains can also mediate heteromeric associations between TM helices (12-14), but the role of packing interactions in driving the formation of specific TM helix heterooligomers has not been systematically studied.We developed a system to study heteromeric TM helix-helix interactions in mamm...

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“…To test whether the E5 dimer can be used as a modular scaffold from which diverse transmembrane amino acid sequences are displayed, we devised a method to select small proteins with novel transmembrane sequences that specifically activated the PDGF b receptor (Freeman-Cook et al, 2004). We constructed a library in which 15 transmembrane amino acids of the E5 protein were replaced with random, hydrophobic amino acids (Figure 1).…”

Section: The Importance Of Transmembrane Interactionsmentioning

confidence: 99%

Modulation of cell function by small transmembrane proteins modeled on the bovine papillomavirus E5 protein

Freeman-Cook

DiMaio

2005

Oncogene

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Selection and Characterization of Small Random Transmembrane Proteins that Bind and Activate the Platelet-derived Growth Factor β Receptor

Cited by 54 publications

References 49 publications

An alternative interpretation of the amyloid Aβ hypothesis with regard to the pathogenesis of Alzheimer's disease

An alternative interpretation of the amyloid Aβ hypothesis with regard to the pathogenesis of Alzheimer's disease

Packing contacts can mediate highly specific interactions between artificial transmembrane proteins and the PDGFβ receptor

Modulation of cell function by small transmembrane proteins modeled on the bovine papillomavirus E5 protein

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