Publisher’s Note: “Lattice model simulation of interchain protein interactions and the folding dynamics and dimerization of the GCN4 Leucine zipper” [J. Chem. Phys. 128, 045106 (2008)]

2008 ◽  
Vol 128 (12) ◽  
pp. 129901 ◽  
Author(s):  
Yanxin Liu ◽  
Prem P. Chapagain ◽  
Jose L. Parra ◽  
Bernard S. Gerstman
Keyword(s):  
Protein Interactions ◽  
Lattice Model ◽  
Leucine Zipper ◽  
Model Simulation ◽  
Chem Phys ◽  
Folding Dynamics

scholarly journals Roles of the 14-3-3 gene family in cotton flowering

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Na Sang ◽  
Hui Liu ◽  
Bin Ma ◽  
Xianzhong Huang ◽  
Lu Zhuo ◽  
...  
Keyword(s):  
Gene Family ◽  
Protein Interactions ◽  
Leucine Zipper ◽  
Expression Patterns ◽  
Bimolecular Fluorescence Complementation ◽  
Structural Motif ◽  
Virus Induced Gene Silencing ◽  
Protein Protein Interactions ◽  
Basic Leucine Zipper ◽  
Genome Wide

Abstract Background In plants, 14-3-3 proteins, also called GENERAL REGULATORY FACTORs (GRFs), encoded by a large multigene family, are involved in protein–protein interactions and play crucial roles in various physiological processes. No genome-wide analysis of the GRF gene family has been performed in cotton, and their functions in flowering are largely unknown. Results In this study, 17, 17, 31, and 17 GRF genes were identified in Gossypium herbaceum, G. arboreum, G. hirsutum, and G. raimondii, respectively, by genome-wide analyses and were designated as GheGRFs, GaGRFs, GhGRFs, and GrGRFs, respectively. A phylogenetic analysis revealed that these proteins were divided into ε and non-ε groups. Gene structural, motif composition, synteny, and duplicated gene analyses of the identified GRF genes provided insights into the evolution of this family in cotton. GhGRF genes exhibited diverse expression patterns in different tissues. Yeast two-hybrid and bimolecular fluorescence complementation assays showed that the GhGRFs interacted with the cotton FLOWERING LOCUS T homologue GhFT in the cytoplasm and nucleus, while they interacted with the basic leucine zipper transcription factor GhFD only in the nucleus. Virus-induced gene silencing in G. hirsutum and transgenic studies in Arabidopsis demonstrated that GhGRF3/6/9/15 repressed flowering and that GhGRF14 promoted flowering. Conclusions Here, 82 GRF genes were identified in cotton, and their gene and protein features, classification, evolution, and expression patterns were comprehensively and systematically investigated. The GhGRF3/6/9/15 interacted with GhFT and GhFD to form florigen activation complexs that inhibited flowering. However, GhGRF14 interacted with GhFT and GhFD to form florigen activation complex that promoted flowering. The results provide a foundation for further studies on the regulatory mechanisms of flowering.

Leucine periodicity of U2 small nuclear ribonucleoprotein particle (snRNP) A' protein is implicated in snRNP assembly via protein-protein interactions

1991 ◽  
Vol 11 (3) ◽  
pp. 1578-1589
Author(s):  
L D Fresco ◽  
D S Harper ◽  
J D Keene
Keyword(s):  
Protein Interactions ◽  
Leucine Zipper ◽  
Tandem Repeats ◽  
Mutational Analysis ◽  
Particle Density ◽  
Protein Protein Interactions ◽  
Small Nuclear Ribonucleoprotein ◽  
Cell Extracts ◽  
Associated Proteins ◽  
Nuclear Ribonucleoprotein

Recombinant A' protein could be reconstituted into U2 small nuclear ribonucleoprotein particles (snRNPs) upon addition to HeLa cell extracts as determined by coimmunoprecipitation and particle density; however, direct binding to U2 RNA could not be demonstrated except in the presence of the U2 snRNP B" protein. Mutational analysis indicated that a central core region of A' was required for particle reconstitution. This region consists of five tandem repeats of approximately 24 amino acids each that exhibit a periodicity of leucine and asparagine residues that is distinct from the leucine zipper. Similar leucine-rich (Leu-Leu motif) repeats are characteristic of a diverse array of soluble and membrane-associated proteins from yeasts to humans but have not been reported previously to reside in nuclear proteins. Several of these proteins, including Toll, chaoptin, RNase/angiogenin inhibitors, lutropin-choriogonadotropin receptor, carboxypeptidase N, adenylyl cyclase, CD14, and human immunodeficiency virus type 1 Rev, may be involved in protein-protein interactions. Our findings suggest that in cell extracts the Leu-Leu motif of A' is required for reconstitution with U2 snRNPs and perhaps with other components involved in splicing through protein-protein interactions.

scholarly journals Properties of the phage-shock-protein (Psp) regulatory complex that govern signal transduction and induction of the Psp response in Escherichia coli

Microbiology ◽  
2010 ◽  
Vol 156 (10) ◽  
pp. 2920-2932 ◽  
Author(s):  
Goran Jovanovic ◽  
Christoph Engl ◽  
Antony J. Mayhew ◽  
Patricia C. Burrows ◽  
Martin Buck
Keyword(s):  
Escherichia Coli ◽  
Signal Transduction ◽  
Protein Interactions ◽  
Leucine Zipper ◽  
Negative Control ◽  
Stress Conditions ◽  
Bacterial Cells ◽  
Protein Protein Interactions ◽  
Regulatory Complex ◽  
And Function

The phage-shock-protein (Psp) response maintains the proton-motive force (pmf) under extracytoplasmic stress conditions that impair the inner membrane (IM) in bacterial cells. In Escherichia coli transcription of the pspABCDE and pspG genes requires activation of σ 54-RNA polymerase by the enhancer-binding protein PspF. A regulatory network comprising PspF–A–C–B–ArcB controls psp expression. One key regulatory point is the negative control of PspF imposed by its binding to PspA. It has been proposed that under stress conditions, the IM-bound sensors PspB and PspC receive and transduce the signal(s) to PspA via protein–protein interactions, resulting in the release of the PspA–PspF inhibitory complex and the consequent induction of psp. In this work we demonstrate that PspB self-associates and interacts with PspC via putative IM regions. We present evidence suggesting that PspC has two topologies and that conserved residue G48 and the putative leucine zipper motif are determinants required for PspA interaction and signal transduction upon stress. We also establish that PspC directly interacts with the effector PspG, and show that PspG self-associates. These results are discussed in the context of formation and function of the Psp regulatory complex.

scholarly journals Transcriptional and DNA Binding Activity of the Foxp1/2/4 Family Is Modulated by Heterotypic and Homotypic Protein Interactions

2004 ◽  
Vol 24 (2) ◽  
pp. 809-822 ◽  
Author(s):  
Shanru Li ◽  
Joel Weidenfeld ◽  
Edward E. Morrisey
Keyword(s):  
Dna Binding ◽  
Protein Interactions ◽  
Leucine Zipper ◽  
Binding Activity ◽  
Transcriptional Repressors ◽  
Transcription Analysis ◽  
Dna Binding Activity ◽  
The Family ◽  
Two Hybrid ◽  
Repression Domain

ABSTRACT Foxp1, Foxp2, and Foxp4 are large multidomain transcriptional regulators belonging to the family of winged-helix DNA binding proteins known as the Fox family. Foxp1 and Foxp2 have been shown to act as transcriptional repressors, while regulatory activity of the recently identified Foxp4 has not been determined. Given the importance of this Fox gene subfamily in neural and lung development, we sought to elucidate the mechanisms by which Foxp1, Foxp2, and Foxp4 repress gene transcription. We show that like Foxp1 and Foxp2, Foxp4 represses transcription. Analysis of the N-terminal repression domain in Foxp1, Foxp2, and Foxp4 shows that this region contains two separate and distinct repression subdomains that are highly homologous termed subdomain 1 and subdomain 2. However, subdomain 2 is not functional in Foxp4. Screening for proteins that interact with subdomains 1 and 2 of Foxp2 using yeast two-hybrid analysis revealed that subdomain 2 binds to C-terminal binding protein 1, which can synergistically repress transcription with Foxp1 and Foxp2, but not Foxp4. Subdomain 1 contains a highly conserved leucine zipper similar to that found in N-myc and confers homo- and heterodimerization to the Foxp1/2/4 family members. These interactions are dependent on the conserved leucine zipper motif. Finally, we show that the integrity of this subdomain is essential for DNA binding, making Foxp1, Foxp2, and Foxp4 the first Fox proteins that require dimerization for DNA binding. These data reveal a complex regulatory mechanism underlying Foxp1, Foxp2, and Foxp4 activity, demonstrating that Foxp1, Foxp2, and Foxp4 are the first Fox proteins reported whose activity is regulated by homo- and heterodimerization.

scholarly journals Domain swapping reveals the modular nature of Fos, Jun, and CREB proteins.

1990 ◽  
Vol 10 (9) ◽  
pp. 4565-4573 ◽  
Author(s):  
L J Ransone ◽  
P Wamsley ◽  
K L Morley ◽  
I M Verma
Keyword(s):  
Dna Binding ◽  
Protein Interactions ◽  
Leucine Zipper ◽  
Chimeric Protein ◽  
Domain Swapping ◽  
Amino Terminus ◽  
Protein Protein Interactions ◽  
Amino Terminal ◽  
Nih 3T3 ◽  
Basic Region

The products of the Jun and Fos proto-oncogenes form a heterodimer that binds to and activates transcription from 12-O-tetradecanoylphorbol-13-acetate-responsive promoter elements (TGACTCA) and AP-1-binding sites (TGACATCA). These two proteins belong to a family of related transcription factors which contain similar domains required for protein dimerization and DNA binding but display different protein and DNA binding specificities. The basic region, required for DNA binding, is followed by a leucine zipper structure, a domain that mediates protein-protein interactions. To assess the role of these two domains in three related proteins, Fos, Jun, and CREB, we carried out extensive domain-swapping analysis. We found that (i) dimers formed by two Jun leucine zipper-containing proteins were unable to bind DNA as efficiently as a Fos-Jun combination, regardless of the source of the basic region; (ii) the Fos leucine zipper was unable to form either homo- or heterodimers with a chimeric protein containing a Fos leucine zipper; (iii) the Fos basic region was capable of binding to an AP-1 site; (iv) replacement of the Jun amino terminus with that of CREB had little effect on dimerization, whereas replacement with the amino terminus of Fos disrupted both protein-protein and protein-DNA interactions; (v) changes in relative affinities of the Fos and Jun basic regions for the AP-1 element were dependent on the secondary contributions of amino-terminal residues; and (vi) the Fos-Jun chimeric constructs cooperated in transcriptional transactivation of the Jun promoter in NIH 3T3 cells.

scholarly journals Leucine periodicity of U2 small nuclear ribonucleoprotein particle (snRNP) A' protein is implicated in snRNP assembly via protein-protein interactions.

1991 ◽  
Vol 11 (3) ◽  
pp. 1578-1589 ◽  
Author(s):  
L D Fresco ◽  
D S Harper ◽  
J D Keene
Keyword(s):  
Protein Interactions ◽  
Leucine Zipper ◽  
Tandem Repeats ◽  
Mutational Analysis ◽  
Particle Density ◽  
Protein Protein Interactions ◽  
Small Nuclear Ribonucleoprotein ◽  
Cell Extracts ◽  
Associated Proteins ◽  
Nuclear Ribonucleoprotein

Recombinant A' protein could be reconstituted into U2 small nuclear ribonucleoprotein particles (snRNPs) upon addition to HeLa cell extracts as determined by coimmunoprecipitation and particle density; however, direct binding to U2 RNA could not be demonstrated except in the presence of the U2 snRNP B" protein. Mutational analysis indicated that a central core region of A' was required for particle reconstitution. This region consists of five tandem repeats of approximately 24 amino acids each that exhibit a periodicity of leucine and asparagine residues that is distinct from the leucine zipper. Similar leucine-rich (Leu-Leu motif) repeats are characteristic of a diverse array of soluble and membrane-associated proteins from yeasts to humans but have not been reported previously to reside in nuclear proteins. Several of these proteins, including Toll, chaoptin, RNase/angiogenin inhibitors, lutropin-choriogonadotropin receptor, carboxypeptidase N, adenylyl cyclase, CD14, and human immunodeficiency virus type 1 Rev, may be involved in protein-protein interactions. Our findings suggest that in cell extracts the Leu-Leu motif of A' is required for reconstitution with U2 snRNPs and perhaps with other components involved in splicing through protein-protein interactions.

scholarly journals A domain shared by the Polycomb group proteins Scm and ph mediates heterotypic and homotypic interactions.

1997 ◽  
Vol 17 (11) ◽  
pp. 6683-6692 ◽  
Author(s):  
A J Peterson ◽  
M Kyba ◽  
D Bornemann ◽  
K Morgan ◽  
H W Brock ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Leucine Zipper ◽  
Point Mutations ◽  
Direct Interaction ◽  
Molecular Complexes ◽  
Polycomb Group ◽  
Ph Domain ◽  
Binding Studies

The Sex comb on midleg (Scm) and polyhomeotic (ph) proteins are members of the Polycomb group (PcG) of transcriptional repressors. PcG proteins maintain differential patterns of homeotic gene expression during development in Drosophila flies. The Scm and ph proteins share a homology domain with 38% identity over a length of 65 amino acids, termed the SPM domain, that is located at their respective C termini. Using the yeast two-hybrid system and in vitro protein-binding assays, we show that the SPM domain mediates direct interaction between Scm and ph. Binding studies with isolated SPM domains from Scm and ph show that the domain is sufficient for these protein interactions. These studies also show that the Scm-ph and Scm-Scm domain interactions are much stronger than the ph-ph domain interaction, indicating that the isolated domain has intrinsic binding specificity determinants. Analysis of site-directed point mutations identifies residues that are important for SPM domain function. These binding properties, predicted alpha-helical secondary structure, and conservation of hydrophobic residues prompt comparisons of the SPM domain to the helix-loop-helix and leucine zipper domains used for homotypic and heterotypic protein interactions in other transcriptional regulators. In addition to in vitro studies, we show colocalization of the Scm and ph proteins at polytene chromosome sites in vivo. We discuss the possible roles of the SPM domain in the assembly or function of molecular complexes of PcG proteins.

scholarly journals The Functional Oligomeric State of Tegument Protein GP41 Is Essential for Baculovirus Budded Virion and Occlusion-Derived Virion Assembly

2018 ◽  
Vol 92 (12) ◽  
Author(s):  
Yimeng Li ◽  
Shu Shen ◽  
Liangbo Hu ◽  
Fei Deng ◽  
Just M. Vlak ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Leucine Zipper ◽  
Close Correlation ◽  
Replication Cycle ◽  
Tegument Protein ◽  
Temperature Sensitive ◽  
Oligomeric State ◽  
Virion Morphogenesis ◽  
Protein Gp41 ◽  
Virion Envelope

ABSTRACTgp41, one of the baculovirus core genes, encodes the only recognized tegument (O-glycosylated) protein of the occlusion-derived virion (ODV) phenotype so far. A previous study using a temperature-sensitive Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) mutant showed that GP41 plays a crucial role in budded virion (BV) formation. However, the precise function of GP41 in the baculovirus replication cycle remains unclear. In this study, AcMNPV GP41 was found to accumulate around the ring zone (RZ) region within the infected nucleus and finally assembled into both BVs and ODVs. Deletion ofgp41from the AcMNPV genome showed that BVs were no longer formed and ODVs were no longer assembled, suggesting the essential role of this gene in baculovirus virion morphogenesis. In infected cells, besides the 42-kDa monomers, dimers and trimers were detected under nonreducing conditions, whereas only trimeric GP41 forms were selectively incorporated into BVs or ODVs. Mutations of all five cysteines in GP41 individually had minor effects on GP41 oligomer formation, albeit certain mutations impaired infectious BV production, suggesting flexibility in the intermolecular disulfide bonding. Single mutations of key leucines within two predicted leucine zipper-like motifs did not interfere with GP41 oligomerization or BV and ODV formation, but double leucine mutations completely blocked oligomerization of GP41 and progeny BV production. In the latter case, the usual subcellular localization, especially RZ accumulation, of GP41 was abolished. The above findings clearly point out a close correlation between GP41 oligomerization and function and therefore highlight the oligomeric state as the functional form of GP41 in the baculovirus replication cycle.IMPORTANCEThe tegument, which is sandwiched between the nucleocapsid and the virion envelope, is an important substructure of many enveloped viruses. It is composed of one or more proteins that have important functions during virus entry, replication, assembly, and egress. Unlike another large DNA virus (herpesvirus) that encodes an extensive set of tegument components, baculoviruses very likely exploit the major tegument protein, GP41, to execute functions in baculovirus virion morphogenesis and assembly. However, the function of this O-glycosylated baculovirus tegument protein remains largely unknown. In this study, we identified trimers as the functional structure of GP41 in baculovirus virion morphogenesis and showed that both disulfide bridging and protein-protein interactions via the two leucine zipper-like domains are involved in the formation of different oligomeric states. This study advances our understanding of the unique viral tegument protein GP41 participating in the life cycle of baculoviruses.

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