scholarly journals Myelin-associated Glycoprotein Interacts with Neurons via a Sialic Acid Binding Site at ARG118 and a Distinct Neurite Inhibition Site

1997 ◽  
Vol 138 (6) ◽  
pp. 1355-1366 ◽  
Author(s):  
Song Tang ◽  
Ying Jing Shen ◽  
Maria Elena DeBellard ◽  
Gitali Mukhopadhyay ◽  
James L. Salzer ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Binding Site ◽  
Neurite Outgrowth ◽  
Binding Protein ◽  
Dependent Manner ◽  
Acid Binding Protein ◽  
Sialic Acid Binding ◽  
Myelin Associated Glycoprotein

Inhibitory components in myelin are largely responsible for the lack of regeneration in the mammalian CNS. Myelin-associated glycoprotein (MAG), a sialic acid binding protein and a component of myelin, is a potent inhibitor of neurite outgrowth from a variety of neurons both in vitro and in vivo. Here, we show that MAG's sialic acid binding site is distinct from its neurite inhibitory activity. Alone, sialic acid–dependent binding of MAG to neurons is insufficient to effect inhibition of axonal growth. Thus, while soluble MAG-Fc (MAG extracellular domain fused to Fc), a truncated form of MAG-Fc missing Ig-domains 4 and 5, MAG(d1-3)-Fc, and another sialic acid binding protein, sialoadhesin, each bind to neurons in a sialic acid– dependent manner, only full-length MAG-Fc inhibits neurite outgrowth. These results suggest that a second site must exist on MAG which elicits this response. Consistent with this model, mutation of arginine 118 (R118) in MAG to either alanine or aspartate abolishes its sialic acid–dependent binding. However, when expressed at the surface of either CHO or Schwann cells, R118-mutated MAG retains the ability to inhibit axonal outgrowth. Hence, MAG has two recognition sites for neurons, the sialic acid binding site at R118 and a distinct inhibition site which is absent from the first three Ig domains.

scholarly journals In vitro and in vivo evidence for actin association of the naphthylphthalamic acid-binding protein from zucchini hypocotyls

1998 ◽  
Vol 13 (3) ◽  
pp. 291-301 ◽  
Author(s):  
John H. Butler ◽  
Shiquan Hu ◽  
Shari R. Brady ◽  
Michael W. Dixon ◽  
Gloria K. Muday
Keyword(s):  
Binding Protein ◽  
Acid Binding Protein ◽  
Naphthylphthalamic Acid

scholarly journals Bartonella henselae Pap31, an Extracellular Matrix Adhesin, Binds the Fibronectin Repeat III13 Module

2006 ◽  
Vol 74 (5) ◽  
pp. 2513-2521 ◽  
Author(s):  
S. M. Dabo ◽  
A. W. Confer ◽  
B. E. Anderson ◽  
Snehalata Gupta
Keyword(s):  
Extracellular Matrix ◽  
Binding Site ◽  
Binding Protein ◽  
Umbilical Vein ◽  
Bartonella Henselae ◽  
Bacterial Attachment ◽  
Dependent Manner ◽  
Host Interaction ◽  
Cloned Gene

ABSTRACT Bartonella henselae wound-associated infections suggest involvement of extracellular matrix molecules in adhesion and invasion. Pap31 was previously identified as a hemin-binding protein. Our recent studies suggest the protein is an adhesin that is recognized by the host's immune systems. In this study we examined the interactions of B. henselae Pap31 with fibronectin (Fn), heparin (Hep), and human umbilical vein endothelial cells (HUVECs). The cloned gene was expressed in Escherichia coli, and the purified Pap31 protein elicited strong antibody responses in mice and was reactive with rabbit anti-live B. henselae and mouse anti-Pap31 antibodies by Western blotting. Pap31 bound to immobilized Fn and to HUVECs in a dose-dependent manner and to Hep. Fn fragment-binding assays identified the Hep-1 and Hep-2 binding domains of human Fn and in particular the 12-13FnIII repeat module as primary binding sites for this adhesin. Furthermore, Pap31 binding to the above Fn fragments could be inhibited by Hep, suggesting a common binding site involving the 13FnIII repeat module on the Hep-2 domain of Fn. Adherence of intact B. henselae to HUVECs was inhibited by increasing concentrations of anti-Pap31 antibodies. In addition, purified Pap31 coprecipitated effectively with Fn and anti-Fn antibodies. Taken together, these data suggest that Pap31 is an Fn-binding protein mediating the B. henselae-host interaction(s), and they implicate the 13FnIII repeat module as an important binding site for this adhesin on the Fn molecule. These interactions may be important initial steps leading to bacterial attachment and colonization that promote the establishment of B. henselae infections in vivo.

scholarly journals Sialic acid-binding lectin from bullfrog eggs inhibits human malignant mesothelioma cell growth in vitro and in vivo

PLoS ONE ◽  
2018 ◽  
Vol 13 (1) ◽  
pp. e0190653 ◽  
Author(s):  
Takeo Tatsuta ◽  
Toshiyuki Satoh ◽  
Shigeki Sugawara ◽  
Akiyoshi Hara ◽  
Masahiro Hosono
Keyword(s):  
Sialic Acid ◽  
Cell Growth ◽  
Malignant Mesothelioma ◽  
Sialic Acid Binding ◽  
Mesothelioma Cell ◽  
Binding Lectin

scholarly journals Incompatibility Protein IncC and Global Regulator KorB Interact in Active Partition of Promiscuous Plasmid RK2

2000 ◽  
Vol 182 (21) ◽  
pp. 6014-6026 ◽  
Author(s):  
Thomas M. Rosche ◽  
Azeem Siddique ◽  
Michelle H. Larsen ◽  
David H. Figurski
Keyword(s):  
Binding Site ◽  
Broad Host Range ◽  
Dependent Manner ◽  
Chromosomal Dna ◽  
Obvious Effect ◽  
Partition System ◽  
Stable Maintenance ◽  
Plasmid Rk2

ABSTRACT Replication of the broad-host-range, IncPα plasmid RK2 requires two plasmid loci: trfA, the replication initiator gene, andoriV, the origin of replication. While these determinants are sufficient for replication in a wide variety of bacteria, they do not confer the stable maintenance of parental RK2 observed in its hosts. The product of the incC gene has been proposed to function in the stable maintenance of RK2 because of its relatedness to the ParA family of ATPases, some of which are known to be involved in the active partition of plasmid and chromosomal DNA. Here we show that IncC has the properties expected of a component of an active partition system. The smaller polypeptide product of incC (IncC2) exhibits a strong, replicon-independent incompatibility phenotype with RK2. This incompatibility phenotype requires the global transcriptional repressor, KorB, and the target for incC-mediated incompatibility is a KorB-binding site (OB). We found that KorB and IncC interact in vivo by using the yeast two-hybrid system and in vitro by using partially purified proteins. Elevated expression of the incC and korB genes individually has no obvious effect on Escherichia coli cell growth, but their simultaneous overexpression is toxic, indicating a possible interaction of IncC-KorB complexes with a vital host target. A region of RK2 bearing incC, korB, and multiple KorB-binding sites is able to stabilize an unstable, heterologous plasmid in anincC-dependent manner. Finally, elevated levels of IncC2 cause RK2 to aggregate, indicating a possible role for IncC in plasmid pairing. These findings demonstrate that IncC, KorB, and at least one KorB-binding site are components of an active partition system for the promiscuous plasmid RK2.

Purification of sialic acid binding protein from saprophytic bacteria by hydrophobic-interaction chromatography on butyl-toyopearl and polymer-coated porous glass

1993 ◽  
Vol 7 (9) ◽  
pp. 667-670 ◽  
Author(s):  
Larisa S. Zhigis ◽  
Alexander E. Ivanov ◽  
Eugenya M. Rapoport ◽  
Emma A. Kovalenko ◽  
Ekaterina I. Getman ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Hydrophobic Interaction ◽  
Porous Glass ◽  
Binding Protein ◽  
Hydrophobic Interaction Chromatography ◽  
Acid Binding Protein ◽  
Sialic Acid Binding

scholarly journals Multivalent interactions with RNA drive RNA binding protein recruitment and dynamics in biomolecular condensates in Xenopus oocytes

2021 ◽  
Author(s):  
Sarah E Cabral ◽  
Kimberly Mowry
Keyword(s):  
Protein Interactions ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Dependent Manner ◽  
Binding Domains ◽  
Multivalent Interactions

RNA localization and biomolecular condensate formation are key biological strategies for organizing the cytoplasm and generating cellular and developmental polarity. While enrichment of RNAs and RNA-binding proteins (RBPs) is a hallmark of both processes, the functional and structural roles of RNA-RNA and RNA-protein interactions within condensates remain unclear. Recent work from our laboratory has shown that RNAs required for germ layer patterning in Xenopus oocytes localize in novel biomolecular condensates, termed Localization bodies (L-bodies). L-bodies are composed of a non-dynamic RNA phase enmeshed in a more dynamic protein-containing phase. However, the interactions that drive the biophysical characteristics of L-bodies are not known. Here, we test the role of RNA-protein interactions using an L-body RNA-binding protein, PTBP3, which contains four RNA-binding domains (RBDs). We find that binding of RNA to PTB is required for both RNA and PTBP3 to be enriched in L-bodies in vivo. Importantly, while RNA binding to a single RBD is sufficient to drive PTBP3 localization to L-bodies, interactions between multiple RRMs and RNA tunes the dynamics of PTBP3 within L-bodies. In vitro, recombinant PTBP3 phase separates into non-dynamic structures in an RNA-dependent manner, supporting a role for RNA-protein interactions as a driver of both recruitment of components to L-bodies and the dynamics of the components after enrichment. Our results point to a model where RNA serves as a concentration-dependent, non-dynamic substructure and multivalent interactions with RNA are a key driver of protein dynamics.

scholarly journals A Sialic Acid-Binding Protein SABP1 of Toxoplasma gondii Mediates Host Cell Attachment and Invasion

2020 ◽  
Vol 222 (1) ◽  
pp. 126-135 ◽  
Author(s):  
Mengen Xing ◽  
Na Yang ◽  
Ning Jiang ◽  
Dawei Wang ◽  
Xiaoyu Sang ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Toxoplasma Gondii ◽  
Host Cell ◽  
Cell Attachment ◽  
Binding Protein ◽  
Critical Role ◽  
Uncharacterized Protein ◽  
Neuraminidase Treatment ◽  
Acid Binding Protein ◽  
Sialic Acid Binding

Abstract Many obligate intracellular apicomplexan parasites have adapted a distinct invasion mechanism involving a close interaction between the parasite ligands and the sialic acid (SA) receptor. We found that sialic acid binding protein-1 (SABP1), localized on the outer membrane of the zoonotic parasite Toxoplasma gondii, readily binds to sialic acid on the host cell surface. The binding was sensitive to neuraminidase treatment. Cells preincubated with recombinant SABP1 protein resisted parasite invasion in vitro. The parasite lost its invasion capacity and animal infectivity after the SABP1 gene was deleted, whereas complementation of the SABP1 gene restored the virulence of the knockout strain. These data establish the critical role of SABP1 in the invasion process of T. gondii. The previously uncharacterized protein, SABP1, facilitated T. gondii attachment and invasion via sialic acid receptors.

Abstract 403: BMPER Is an Angiogenic Modulator that is Regulated by KLF-15 and FoxO3A and Controls Bone Morphogentic Protein Activity

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Thomas Helbing ◽  
Jennifer Heinke ◽  
Franziska Volkmar ◽  
Leonie Wehofsits ◽  
Kim-Miriam Baar ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Binding Site ◽  
Luciferase Expression ◽  
Dependent Manner ◽  
Protein Activity ◽  
Angiogenic Activity ◽  
Bmp Pathway ◽  
Vasculogenesis And Angiogenesis

BMPER (bone morphogenetic protein [BMP] endothelial precursor cell derived regulator) is an extracellular protein, that interacts with BMPs and thereby modulates BMP dependent vasculogenesis and angiogenesis. Our previous observations suggest a complex regulation of BMPER expression. During embryogenesis BMPER is expressed at the time and at sites of vasculogenesis, whereas in the adult organism it is expressed in heart, lung and skin. Methods and Results: We have cloned the mouse BMPER promoter and appropriate deletion constructs into pGL3 to regulate luciferase expression. As predicted in silicio, we found that Sp1 and Sp1-like transcription factors such as the krueppel-like factors (KLFs) regulate BMPER transcription. KLF-15 resulted in a 4.5 fold upregulation. Accordingly, BMPER expression was inhibited by the Sp-1/SP-1 like inhibitor mitramycin A. Site specific mutation of a proximal KLF-15 binding site reduced the effect of KLF-15 on BMPER expression. Along the same lines, knock down of KLF-15 in HUVEC by siRNA reduced BMPER expression. The transactivating effect of KLF-15 could be competed away by coexpression of Sp-1 suggesting that both factors may compete for the same binding site in the BMPER promoter. In EMSA, an oligo representing a well characterized KLF-15 binding site in the AceCs2 promoter but not an oligo encoding for a NFkappa-B site competed with the oligo coding for the KLF-15 site in the BMPER promoter. In contrast FoxO3A, a member of the FoxO family of transcription factors, serves as an inhibitor of BMPER expression, as shown by gain and lack of FoxO3A experiments. Additionally, we found that BMPER stimulates angiogenesis in a BMP-4 dependent manner in several in vitro and in vivo assays. Vice versa, BMPER is necessary for BMP-4 to exert is angiogenic activity on endothelial cells. Conclusion: BMPER is upregulated by KLF-15 and inhibited by FoxO3a. BMPER has angiogenic activity and is a key modulator of the BMP pathway.

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