scholarly journals Disruption of the proline rich region/protein 4.1 binding domain on the endothelial Isoc channel inhibits intercellular gap formation

2006 ◽  
Vol 20 (4) ◽  
Author(s):  
Christina L. Barry ◽  
Donna L. Cioffi ◽  
Songwei Wu ◽  
Troy Stevens
Keyword(s):  
Binding Domain ◽  
Gap Formation ◽  
Rich Region ◽  
Protein 4.1 ◽  
Proline Rich Region

scholarly journals Second-Site Changes Affect Viability of Amphotropic/Ecotropic Chimeric Enveloped Murine Leukemia Viruses

2000 ◽  
Vol 74 (2) ◽  
pp. 899-913 ◽  
Author(s):  
Lucille O'Reilly ◽  
Monica J. Roth
Keyword(s):  
Receptor Binding ◽  
Single Point ◽  
Cell Types ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Rich Region ◽  
C Terminus ◽  
Nih 3T3 ◽  
Proline Rich Region ◽  
Murine Leukemia

ABSTRACT Chimeras were previously generated between the ecotropic (Moloney-MuLV) and amphotropic (4070A) SU and TM proteins of murine leukemia virus (MuLV). After passage in D17 cells, three chimeras with junctions in the C terminus of SU (AE5, AE6, and AE7), showed improved kinetics of viral spreading, suggesting that they had adapted. Sequencing of the viruses derived from the D17 cell lines revealed second-site changes within the env gene. Changes were detected in the receptor binding domain, the proline-rich region, the C terminus of SU, and the ectodomain of TM. Second-site changes were subcloned into the parental DNA, singly and in combination, and tested for viability. All viruses had maintained their original cloned mutations and junctions. Reconstruction and passage of AE7 or AE6 virus with single point mutations recovered the additional second-site changes identified in the parental population. The AE5 isolate required changes in the VRA, the VRC, the VRB-hinge region, and the C terminus of SU for efficient infection. Passage of virus, including the parental 4070A, in D17 cells resulted in a predominant G100R mutation within the receptor binding domain. Viruses were subjected to titer determination in three cell types, NIH 3T3, canine D17, and 293T. AE6 viruses with changes in the proline-rich region initially adapted for growth on D17 cells could infect all cell types tested. AE6-based chimeras with additional mutations in the C terminus of SU could infect D17 and 293T cells. Infection of NIH 3T3 cells was dependent on the proline-rich mutation. AE7-based chimeras encoding L538Q and G100R were impaired in infecting NIH 3T3 and 293T cells.

scholarly journals Regulatory mechanisms for the axonal localization of tau in neurons

2018 ◽  
Author(s):  
Minori Iwata ◽  
Shoji Watanabe ◽  
Ayaka Yamane ◽  
Tomohiro Miyasaka ◽  
Hiroaki Misonou
Keyword(s):  
Hippocampal Neurons ◽  
Neuronal Development ◽  
Experimental System ◽  
Binding Domain ◽  
Rich Region ◽  
Phosphorylation State ◽  
Microtubule Binding Domain ◽  
Mature Neuron ◽  
Early Expression ◽  
Proline Rich Region

AbstractTau is a microtubule (MT)-associated protein, which precisely localizes to the axon of a mature neuron. Although it has been widely used as an axonal marker, the mechanisms for its axonal localization have been elusive. This might be largely due to the lack of an experimental system, as exogenously expressed tau, such as GFP-tau, mis-localizes to the soma and dendrites. In this study, we found that the expression of endogenous tau and its axonal localization in cultured rat hippocampal neurons mainly occur during early neuronal development and are coupled. By mimicking this early expression, we demonstrate that exogenously expressed human tau can be properly localized to the axon, thereby providing the first experimental model to study the mechanisms of tau localization. Using this model, we obtained surprising findings that the axonal localization of tau did not require the MT-binding domain nor correlate with the MT-binding ability. Instead, we identified a transport mechanism mediated by the proline-rich region 2 (PRR2), which contains a number of important phosphorylation sites. Mimicking phosphorylation and dephosphorylation in PRR2 disrupts the axonal localization, suggesting that it is regulated by the phosphorylation state of PRR2. These results shed new lights on the mechanism for the axonal localization of tau and indicate a link between the hyperphosphorylation and mis-localization of tau observed in tauopathies.Significance statementIn this paper, we present a first experimental system, in which expressed tau is properly localized to the axon, and which can therefore be used to study the mechanisms of tau localization and mis-localization. Using this system, we provide evidence that the microtubule binding domain of tau nor stable binding of tau to microtubules is not necessary for its axonal localization. Instead, we identified the proline-rich region and its phosphorylation-state dictate the localization of tau in neurons. These results provide a novel foundation to consider how axonal tau mis-localize to the soma and dendrites during early pathogenesis of Alzheimer’s disease.

scholarly journals Regulation of tau’s proline rich region by its N-terminal domain

2019 ◽  
Author(s):  
Kristen McKibben ◽  
Elizabeth Rhoades
Keyword(s):  
Binding Domain ◽  
Rich Region ◽  
Tau Function ◽  
Microtubule Binding ◽  
Intrinsically Disordered ◽  
Terminal Domain ◽  
Microtubule Polymerization ◽  
Tubulin Binding ◽  
Proline Rich Region

AbstractTau is an intrinsically disordered, microtubule-associated protein with a role in regulating microtubule dynamics. Despite intensive research, the molecular mechanisms of taumediated microtubule polymerization are poorly understood. Here we use single molecule fluorescence to investigate the role of tau’s N-terminal domain (NTD) and proline rich region (PRR) in regulating interactions of tau with soluble tubulin. Both full-length tau isoforms and truncated variants are assayed for their ability to bind soluble tubulin and stimulate microtubule polymerization. We describe a novel role for tau’s PRR as an independent tubulin-binding domain with polymerization capacity. In contrast to the relatively weak tubulin interactions distributed throughout the microtubule binding repeats (MTBR), resulting in heterogeneous tau:tubulin complexes, the PRR binds tubulin tightly and stoichiometrically. Moreover, we demonstrate that interactions between the PRR and MTBR are reduced by the NTD through a conserved conformational ensemble. Based on our data, we propose that tau’s PRR can serve as a core tubulin-binding domain, while the MTBR enhances polymerization capacity by increasing the local tubulin concentration. The NTD negatively regulates tubulin-binding interactions of both of these domains. This study draws attention to the central role of the PRR in tau function, as well as providing mechanistic insight into tau-mediated polymerization of tubulin.Significance StatementTau is an intrinsically disordered, microtubule associated protein linked to a number of neurodegenerative disorders. Here we identify tau’s proline rich region as having autonomous tubulin binding and polymerization capacity, which is enhanced by the flanking microtubule binding repeats. Moreover, we demonstrate that tau’s N-terminal domain negatively regulates both binding and polymerization. We propose a novel model for tau-mediated polymerization whereby the proline rich region serves as a core tubulin-binding domain, while the microtubule binding repeats increase the local concentration. Our work draws attention to the importance of the proline rich region and N-terminal domain in tau function, and highlights the proline rich region as a putative target for the development of therapeutics.

scholarly journals Vaccine-induced, but not natural immunity, against the Streptococcal inhibitor of complement protects against invasive disease

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Lionel K. K. Tan ◽  
Mark Reglinski ◽  
Daryl Teo ◽  
Nada Reza ◽  
Lucy E. M. Lamb ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Natural Infection ◽  
Invasive Disease ◽  
Full Length ◽  
Natural Immunity ◽  
Rich Region ◽  
Antibody Recognition ◽  
Naturally Occurring ◽  
Protective Antibodies ◽  
Proline Rich Region

AbstractHighly pathogenic emm1 Streptococcus pyogenes strains secrete the multidomain Streptococcal inhibitor of complement (SIC) that binds and inactivates components of the innate immune response. We aimed to determine if naturally occurring or vaccine-induced antibodies to SIC are protective against invasive S. pyogenes infection. Immunisation with full-length SIC protected mice against systemic bacterial dissemination following intranasal or intramuscular infection with emm1 S. pyogenes. Vaccine-induced rabbit anti-SIC antibodies, but not naturally occurring human anti-SIC antibodies, enhanced bacterial clearance in an ex vivo whole-blood assay. SIC vaccination of both mice and rabbits resulted in antibody recognition of all domains of SIC, whereas naturally occurring human anti-SIC antibodies recognised the proline-rich region of SIC only. We, therefore, propose a model whereby natural infection with S. pyogenes generates non-protective antibodies against the proline-rich region of SIC, while vaccination with full-length SIC permits the development of protective antibodies against all SIC domains.

A Proline-Rich Region in the Zeste Protein Essential for Transvection and white Repression by Zeste1

Genetics ◽  
1998 ◽  
Vol 148 (4) ◽  
pp. 1865-1874
Author(s):  
Christina Rosen ◽  
Dale Dorsett ◽  
Joseph Jack
Keyword(s):  
Dna Binding ◽  
Protein Interactions ◽  
Homologous Chromosome ◽  
Protein Complexes ◽  
Dna Binding Protein ◽  
Polycomb Group ◽  
The Self ◽  
Rich Region ◽  
Interaction Domain ◽  
Proline Rich Region

Abstract The DNA-binding protein encoded by the zeste gene of Drosophila activates transcription and mediates interchromosomal interactions such as transvection. The mutant protein encoded by the zeste1 (z1) allele retains the ability to support transvection, but represses white. Similar to transvection, repression requires Zeste-Zeste protein interactions and a second copy of white, either on the homologous chromosome or adjacent on the same chromosome. We characterized two pseudorevertants of z1 (z1-35 and z1-42) and another zeste mutation (z78c) that represses white. The z1 lesion alters a lysine residue located between the N-terminal DNA-binding domain and the C-terminal hydrophobic repeats involved in Zeste self-interactions. The z78c mutation alters a histidine near the site of the z1 lesion. Both z1 pseudorevertants retain the z1 lesion and alter different prolines in a proline-rich region located between the z1 lesion and the self-interaction domain. The pseudorevertants retain the ability to self-interact, but fail to repress white or support transvection at Ultrabithorax. To account for these observations and evidence indicating that Zeste affects gene expression through Polycomb group (Pc-G) protein complexes that epigenetically maintain chromatin states, we suggest that the regions affected by the z1, z78c, and pseudorevertant lesions mediate interactions between Zeste and the maintenance complexes.

Identification and functional characterization of a novel human protein highly related to the yeast dynamin-like GTPase Vps1p

1998 ◽  
Vol 111 (10) ◽  
pp. 1341-1349 ◽  
Author(s):  
M. Imoto ◽  
I. Tachibana ◽  
R. Urrutia
Keyword(s):  
Endoplasmic Reticulum ◽  
Cho Cells ◽  
Mammalian Cells ◽  
Functional Characterization ◽  
Luciferase Reporter ◽  
Pleckstrin Homology ◽  
Rich Region ◽  
Gtpase Domain ◽  
Proline Rich Region

Dynamin proteins containing a GTPase domain, a pleckstrin homology motif and a proline-rich tail participate in receptor-mediated endocytosis in organisms ranging from insects to vertebrates. In addition, dynamin-related GTPases, such as the yeast Golgi protein Vps1p, which lack both the pleckstrin homology motif and the proline-rich region, participate in vesicular transport within the secretory pathway in lower eukaryotes. However, no data is available on the existence of Vps1p-like proteins in mammalian cells. In this study, we report the identification and characterization of a novel gene encoding a human dynamin-related protein, DRP1, displaying high similarity to the Golgi dynamin-like protein Vps1p from yeast and to a Caenorhabditis elegans protein deposited in the databank. These proteins are highly conserved in their N-terminal tripartite GTPase domain but lack the pleckstrin homology motif and proline-rich region. Northern blot analysis reveals that the DRP1 mRNA is detected at high levels in human muscle, heart, kidney and brain. Immunolocalization studies in Chinese hamster ovary (CHO) cells using an epitope-tagged form of DRP1 and confocal microscopy show that this protein is concentrated in a perinuclear region that labels with the endoplasmic reticulum marker DiOC6(3) and the Golgi marker C5-DMB-Cer. In addition, the localization of DRP1 is highly similar to the localization of the endoplasmic reticulum and cis-Golgi GTPase Rab1A, but not to the staining for the trans-Golgi GTPase Rab6. Furthermore, overexpression of a cDNA encoding a GTP binding site mutant of DRP1 (DRP1(K38E)) in CHO cells decreases the amount of a secreted luciferase reporter protein, whereas the overexpression of wild-type DRP1 increases the secretion of this marker. Together, these results constitute the first structural and functional characterization of a mammalian protein similar to the yeast dynamin-related GTPase Vps1p and indicate that the participation of these proteins in secretion has been conserved throughout evolution.

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