scholarly journals Characterization of a cDNA encoding RP43, a CUB-domain-containing protein from the tube of Riftia pachyptila (Vestimentifera), and distribution of its transcript

2000 ◽  
Vol 350 (2) ◽  
pp. 421-427 ◽  
Author(s):  
Luc CHAMOY ◽  
Maryse NICOLAÏ ◽  
Brigitte QUENNEDEY ◽  
Françoise GAILL ◽  
Jean DELACHAMBRE
Keyword(s):  
Protein Interactions ◽  
Hydrothermal Vents ◽  
Unexpected Result ◽  
Protein Protein Interactions ◽  
Riftia Pachyptila ◽  
Binding Motifs ◽  
Morphogenetic Protein ◽  
Protective Tube ◽  
Cub Domain ◽  
Rapid Amplification

A major 43kDa protein from the protective tube of Riftiapachyptila (Vestimentifera), named RP43, was partly microsequenced after isolation by SDS/PAGE from the protein fraction of tubes collected around the hydrothermal vents at the East Pacific Rise. On the basis of the partial peptide sequences obtained, experiments using reverse-transcriptase-mediated PCR and rapid amplification of cDNA ends led to the complete cDNA sequence. Analysis of deduced amino acid sequence of RP43 showed the presence of CUB domains (100–110-residue-spanning domains first reported in the complement subcomponents C1r/C1s, epidermal-growth-factor-related sea urchin protein and bone morphogenetic protein 1) that seem to be involved in protein–protein and glycosaminoglycan–protein interactions. This peculiarity strongly suggests that RP43 might have a crucial role in tightening the different elements of the worm tube. However, the absence of chitin-binding motifs inclines us to favour a role in protein–protein interactions during assembly of the tube components. The RP43 mRNA was found to be present in specific epidermal cells from the worm body wall but never in the chitin-synthesizing gland cells. This unexpected result clearly indicates that the major tube protein is synthesized in specialized areas of the outer epithelium and that at least two different tissues are involved in the synthesis of the exoskeleton.

scholarly journals ArabidopsisImmunophilin-like TWD1 Functionally Interacts with Vacuolar ABC Transporters

2004 ◽  
Vol 15 (7) ◽  
pp. 3393-3405 ◽  
Author(s):  
Markus Geisler ◽  
Marjolaine Girin ◽  
Sabine Brandt ◽  
Vincent Vincenzetti ◽  
Sonia Plaza ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Abc Transporters ◽  
Loss Of Function ◽  
Protein Protein Interactions ◽  
Binding Motifs ◽  
Calmodulin Binding ◽  
C Terminus ◽  
Domain Mapping ◽  
Tetratricopeptide Repeat Domain

Previously, the immunophilin-like protein TWD1 from Arabidopsis has been demonstrated to interact with the ABC transporters AtPGP1 and its closest homologue, AtPGP19. Physiological and biochemical investigation of pgp1/pgp19 and of twd1 plants suggested a regulatory role of TWD1 on AtPGP1/AtPGP19 transport activities. To further understand the dramatic pleiotropic phenotype that is caused by loss-of-function mutation of the TWD1 gene, we were interested in other TWD1 interacting proteins. AtMRP1, a multidrug resistance-associated (MRP/ABCC)-like ABC transporter, has been isolated in a yeast two-hybrid screen. We demonstrate molecular interaction between TWD1 and ABC transporters AtMRP1 and its closest homologue, AtMRP2. Unlike AtPGP1, AtMRP1 binds to the C-terminal tetratricopeptide repeat domain of TWD1, which is well known to mediate protein-protein interactions. Domain mapping proved that TWD1 binds to a motif of AtMRP1 that resembles calmodulin-binding motifs; and calmodulin binding to the C-terminus of MRP1 was verified. By membrane fractionation and GFP-tagging, we localized AtMRP1 to the central vacuolar membrane and the TWD1-AtMRP1 complex was verified in vivo by coimmunoprecipitation. We were able to demonstrate that TWD1 binds to isolated vacuoles and has a significant impact on the uptake of metolachlor-GS and estradiol-β-glucuronide, well-known substrates of vacuolar transporters AtMRP1 and AtMRP2.

scholarly journals De novocoiled-coil peptides as scaffolds for disrupting protein–protein interactions

2018 ◽  
Vol 9 (39) ◽  
pp. 7656-7665 ◽  
Author(s):  
Jordan M. Fletcher ◽  
Katherine A. Horner ◽  
Gail J. Bartlett ◽  
Guto G. Rhys ◽  
Andrew J. Wilson ◽  
...  
Keyword(s):  
Protein Binding ◽  
Protein Interactions ◽  
Coiled Coils ◽  
Protein Protein Interactions ◽  
Binding Motifs ◽  
Helical Protein

Homo- and hetero-dimeric coiled coils as scaffolds for the presentation of α-helical protein-binding motifs.

A mutation outside the two zinc fingers of ADR1 can suppress defects in either finger

1992 ◽  
Vol 12 (12) ◽  
pp. 5758-5767
Author(s):  
S Camier ◽  
N Kacherovsky ◽  
E T Young
Keyword(s):  
Dna Binding ◽  
Protein Interactions ◽  
Zinc Fingers ◽  
Wild Type ◽  
Protein Protein Interactions ◽  
Site Mutation ◽  
Binding Motifs ◽  
Amino Terminal ◽  
Sequence Homologies ◽  
In The Wild

A second-site mutation that restored DNA binding to ADR1 mutants altered at different positions in the two zinc fingers was identified. This mutation (called IS1) was a conservative change of arginine 91 to lysine in a region amino terminal to the two zinc fingers and known from previous experiments to be necessary for DNA binding. IS1 increased binding to the UAS1 sequence two- to sevenfold for various ADR1 mutants and twofold for wild-type ADR1. The change of arginine 91 to glycine decreased binding twofold, suggesting that this arginine is involved in DNA binding in the wild-type protein. The increase in binding by IS1 did not involve protein-protein interactions between the two ADR1 monomers, nor did it require the presence of the sequences flanking UAS1. However, the effect of IS1 was influenced by the sequence of the first finger, suggesting that interactions between the region amino terminal to the fingers and the fingers themselves could exist. A model for the role of the amino-terminal region based on these results and sequence homologies with other DNA-binding motifs is proposed.

scholarly journals Analysis of the Signaling Activities of Localization Mutants of β-Catenin during Axis Specification in Xenopus

1997 ◽  
Vol 139 (1) ◽  
pp. 229-243 ◽  
Author(s):  
Jeffrey R. Miller ◽  
Randall T. Moon
Keyword(s):  
Cell Fate ◽  
Protein Interactions ◽  
Glycogen Synthase ◽  
Regulation Of Gene Expression ◽  
Unexpected Result ◽  
Protein Protein Interactions ◽  
Cell Fates ◽  
Xenopus Embryos ◽  
Axis Specification ◽  
Dorsal Cell Fate

In Xenopus embryos, β-catenin has been shown to be both necessary and sufficient for the establishment of dorsal cell fates. This signaling activity is thought to depend on the binding of β-catenin to members of the Lef/Tcf family of transcription factors and the regulation of gene expression by this complex. To test whether β-catenin must accumulate in nuclei to establish dorsal cell fate, we constructed various localization mutants that restrict β-catenin to either the plasma membrane, the cytosol, or the nucleus. When overexpressed in Xenopus embryos, the proteins localize as predicted, but surprisingly all forms induce an ectopic axis, indicative of inducing dorsal cell fates. Given this unexpected result, we focused on the membrane-tethered form of β-catenin to resolve the apparent discrepancy between its membrane localization and the hypothesized role of nuclear β-catenin in establishing dorsal cell fate. We demonstrate that overexpression of membrane-tethered β-catenin elevates the level of free endogenous β-catenin, which subsequently accumulates in nuclei. Consistent with the hypothesis that it is this pool of non–membrane-associated β-catenin that signals in the presence of membrane-tethered β-catenin, overexpression of cadherin, which binds free β-catenin, blocks the axis-inducing activity of membrane- tethered β-catenin. The mechanism by which ectopic membrane-tethered β-catenin increases the level of endogenous β-catenin likely involves competition for the adenomatous polyposis coli (APC) protein, which in other systems has been shown to play a role in degradation of β-catenin. Consistent with this hypothesis, membrane-tethered β-catenin coimmunoprecipitates with APC and relocalizes APC to the membrane in cells. Similar results are observed with ectopic plakoglobin, casting doubt on a normal role for plakoglobin in axis specification and indicating that ectopic proteins that interact with APC can artifactually elevate the level of endogenous β-catenin, likely by interfering with its degradation. These results highlight the difficulty in interpreting the activity of an ectopic protein when it is assayed in a background containing the endogenous protein. We next investigated whether the ability of β-catenin to interact with potential protein partners in the cell may normally be regulated by phosphorylation. Compared with nonphosphorylated β-catenin, β-catenin phosphorylated by glycogen synthase kinase-3 preferentially associates with microsomal fractions expressing the cytoplasmic region of N-cadherin. These results suggest that protein–protein interactions of β-catenin can be influenced by its state of phosphorylation, in addition to prior evidence that this phosphorylation modulates the stability of β-catenin.

scholarly journals On the specificity of protein–protein interactions in the context of disorder

2021 ◽  
Vol 478 (11) ◽  
pp. 2035-2050
Author(s):  
Kaare Teilum ◽  
Johan G. Olsen ◽  
Birthe B. Kragelund
Keyword(s):  
Protein Interactions ◽  
Intrinsically Disordered Proteins ◽  
Globular Proteins ◽  
Disordered Proteins ◽  
Protein Protein Interactions ◽  
Binding Motifs ◽  
Intrinsically Disordered ◽  
Binding Partners ◽  
Trimer Formation ◽  
Definition Of

With the increased focus on intrinsically disordered proteins (IDPs) and their large interactomes, the question about their specificity — or more so on their multispecificity — arise. Here we recapitulate how specificity and multispecificity are quantified and address through examples if IDPs in this respect differ from globular proteins. The conclusion is that quantitatively, globular proteins and IDPs are similar when it comes to specificity. However, compared with globular proteins, IDPs have larger interactome sizes, a phenomenon that is further enabled by their flexibility, repetitive binding motifs and propensity to adapt to different binding partners. For IDPs, this adaptability, interactome size and a higher degree of multivalency opens for new interaction mechanisms such as facilitated exchange through trimer formation and ultra-sensitivity via threshold effects and ensemble redistribution. IDPs and their interactions, thus, do not compromise the definition of specificity. Instead, it is the sheer size of their interactomes that complicates its calculation. More importantly, it is this size that challenges how we conceptually envision, interpret and speak about their specificity.

scholarly journals Physical Interaction between Coat Morphogenetic Proteins SpoVID and CotE Is Necessary for Spore Encasement in Bacillus subtilis

2012 ◽  
Vol 194 (18) ◽  
pp. 4941-4950 ◽  
Author(s):  
Melissa de Francesco ◽  
Jake Z. Jacobs ◽  
Filipa Nunes ◽  
Mónica Serrano ◽  
Peter T. McKenney ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Protein Interactions ◽  
Mutational Analysis ◽  
Physical Interaction ◽  
Spore Coat ◽  
Coat Proteins ◽  
Protein Protein Interactions ◽  
Content Type ◽  
Morphogenetic Protein ◽  
Physical Interactions

ABSTRACTEndospore formation byBacillus subtilisis a complex and dynamic process. One of the major challenges of sporulation is the assembly of a protective, multilayered, proteinaceous spore coat, composed of at least 70 different proteins. Spore coat formation can be divided into two distinct stages. The first is the recruitment of proteins to the spore surface, dependent on the morphogenetic protein SpoIVA. The second step, known as encasement, involves the migration of the coat proteins around the circumference of the spore in successive waves, a process dependent on the morphogenetic protein SpoVID and the transcriptional regulation of individual coat genes. We provide genetic and biochemical evidence supporting the hypothesis that SpoVID promotes encasement of the spore by establishing direct protein-protein interactions with other coat morphogenetic proteins. It was previously demonstrated that SpoVID directly interacts with SpoIVA and the inner coat morphogenetic protein, SafA. Here, we show by yeast two-hybrid and pulldown assays that SpoVID also interacts directly with the outer coat morphogenetic protein, CotE. Furthermore, by mutational analysis, we identified a specific residue in the N-terminal domain of SpoVID that is essential for the interaction with CotE but dispensable for the interaction with SafA. We propose an updated model of coat assembly and spore encasement that incorporates several physical interactions between the principal coat morphogenetic proteins.

scholarly journals Regulation of the phosphatase PP2B by protein–protein interactions

2016 ◽  
Vol 44 (5) ◽  
pp. 1313-1319 ◽  
Author(s):  
Patrick J. Nygren ◽  
John D. Scott
Keyword(s):  
Protein Interactions ◽  
Protein Phosphatase ◽  
Therapeutic Benefit ◽  
Protein Protein Interactions ◽  
Binding Motifs ◽  
Protein Substrates ◽  
Protein Phosphatase 2B ◽  
Anchoring Protein ◽  
Protein Dephosphorylation

Protein dephosphorylation is important for regulating cellular signaling in a variety of contexts. Protein phosphatase-2B (PP2B), or calcineurin, is a widely expressed serine/threonine phosphatase that acts on a large cross section of potential protein substrates when activated by increased levels of intracellular calcium in concert with calmodulin. PxIxIT and LxVP targeting motifs are important for maintaining specificity in response to elevated calcium. In the present study, we describe the mechanism of PP2B activation, discuss its targeting by conserved binding motifs and review recent advances in the understanding of an A-kinase anchoring protein 79/PP2B/protein kinase A complex's role in synaptic long-term depression. Finally, we discuss potential for targeting PP2B anchoring motifs for therapeutic benefit.

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