scholarly journals THE STRUCTURAL BASIS FOR BINDING OF COMPLEMENT BY IMMUNOGLOBULIN M

1974 ◽  
Vol 140 (4) ◽  
pp. 1117-1121 ◽  
Author(s):  
Mary M. Hurst ◽  
John E. Volanakis ◽  
Raymond B. Hester ◽  
Robert M. Stroud ◽  
J. Claude Bennett
Keyword(s):  
Amino Acid ◽  
Structural Features ◽  
Immunoglobulin M ◽  
Structural Basis ◽  
Amino Acid Residues ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Carboxy Terminal Domain ◽  
Carboxy Terminal ◽  
Insight Into

An insight into the structural features of human IgM that are responsible for its capacity to bind the first component of complement (C) has been obtained by examining the ability of IgM subfragments to bind active C1 (C1). The smallest two fragments found to bind C1 were the major CNBr fragment of the Fc portion of IgM and the CH4 fragment of the carboxy-terminal domain. The smallest fragment which fixes C1 has a disaggregated mol wt of 6,800, consists of 60 residues, and contains no carbohydrate. Structural considerations and sequence overlaps suggest that the amino-terminal side of the CH4 domain (24 amino acid residues) might be responsible for fixing C1.

scholarly journals The Carboxy-Terminal Domain of Hsc70 Provides Binding Sites for a Distinct Set of Chaperone Cofactors

1998 ◽  
Vol 18 (4) ◽  
pp. 2023-2028 ◽  
Author(s):  
Jens Demand ◽  
Jens Lüders ◽  
Jörg Höhfeld
Keyword(s):  
Binding Sites ◽  
Mammalian Cells ◽  
Chaperone Activity ◽  
Structural Basis ◽  
Atpase Domain ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Chaperone Protein ◽  
Carboxy Terminal Domain ◽  
Carboxy Terminal

ABSTRACT The modulation of the chaperone activity of the heat shock cognate Hsc70 protein in mammalian cells involves cooperation with chaperone cofactors, such as Hsp40; BAG-1; the Hsc70-interacting protein, Hip; and the Hsc70-Hsp90-organizing protein, Hop. By employing the yeast two-hybrid system and in vitro interaction assays, we have provided insight into the structural basis that underlies Hsc70’s cooperation with different cofactors. The carboxy-terminal domain of Hsc70, previously shown to form a lid over the peptide binding pocket of the chaperone protein, mediates the interaction of Hsc70 with Hsp40 and Hop. Remarkably, the two cofactors bind to the carboxy terminus of Hsc70 in a noncompetitive manner, revealing the existence of distinct binding sites for Hsp40 and Hop within this domain. In contrast, Hip interacts exclusively with the amino-terminal ATPase domain of Hsc70. Hence, Hsc70 possesses separate nonoverlapping binding sites for Hsp40, Hip, and Hop. This appears to enable the chaperone protein to cooperate simultaneously with multiple cofactors. On the other hand, BAG-1 and Hip have recently been shown to compete in binding to the ATPase domain. Our data thus establish the existence of a network of cooperating and competing cofactors regulating the chaperone activity of Hsc70 in the mammalian cell.

scholarly journals Alternatively spliced forms in the carboxy-terminal domain of the p53 protein regulate its ability to promote annealing of complementary single strands of nucleic acids.

1995 ◽  
Vol 15 (1) ◽  
pp. 497-504 ◽  
Author(s):  
L Wu ◽  
J H Bayle ◽  
B Elenbaas ◽  
N P Pavletich ◽  
A J Levine
Keyword(s):  
Amino Acid ◽  
Alternative Splice ◽  
P53 Protein ◽  
Amino Acid Residues ◽  
Terminal Domain ◽  
Carboxy Terminal Domain ◽  
Alternatively Spliced ◽  
Carboxy Terminal ◽  
Splice Forms ◽  
Cancerous Cells

The carboxy-terminal domain of the p53 protein comprising amino acid residues 311 to 393 is able to promote the reassociation of single-stranded RNA or DNA into duplex hybrids. This domain is as efficient as the intact p53 protein in both the rate and the extent of the double-stranded product produced in this reaction. Both wild-type and mutant p53 proteins from cancerous cells carry out this reaction. The monoclonal antibody PAb421, which detects an epitope between residues 370 and 378, blocks the ability of p53 to reassociate single strands of RNA or DNA. Similarly, the alternative splice form of the murine p53 protein, which removes amino acid residues 364 to 390 and replaces them with 17 new amino acids, does not carry out the reassociation reaction with RNA or DNA. This is the first indication of functionally distinct properties of the alternative splice forms of p53. These results suggest that this splice alternative can regulate a p53-mediated reaction that may be related to the functions of this protein.

scholarly journals p190 RhoGAP, the major RasGAP-associated protein, binds GTP directly.

1994 ◽  
Vol 14 (11) ◽  
pp. 7173-7181 ◽  
Author(s):  
R Foster ◽  
K Q Hu ◽  
D A Shaywitz ◽  
J Settleman
Keyword(s):  
Structural Features ◽  
Cellular Protein ◽  
Small Gtpases ◽  
Sequence Motifs ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Gtp Binding ◽  
Guanine Nucleotide Binding ◽  
Complex Forms ◽  
Carboxy Terminal

In mitogenically stimulated cells, a specific complex forms between the Ras GTPase-activating protein (RasGAP) and the cellular protein p190. We have previously reported that p190 contains a carboxy-terminal domain that functions as a GAP for the Rho family GTPases. Thus, the RasGAP-p190 complex may serve to couple Ras- and Rho-mediated signalling pathways. In addition to its RhoGAP domain, p190 contains an amino-terminal domain that contains sequence motifs found in all known GTPases. Here, we report that p190 binds GTP and GDP through this conserved domain and that the structural requirements for binding are similar to those seen with other GTPases. While the purified protein is unable to hydrolyze GTP, we detect an activity in cell lysates that can promote GTP hydrolysis by p190. A mutated form of p190 that fails to bind nucleotide retains its RasGAP binding and RhoGAP activities, indicating that GTP binding by p190 is not required for these functions. The sequence of p190 in the GTP-binding domain, which shares structural features with both the Ras-like small GTPases and the larger G proteins, suggests that this protein defines a novel class of guanine nucleotide-binding proteins.

Disruption of dynamic cell surface architecture of NIH3T3 fibroblasts by the N-terminal domains of moesin and ezrin: in vivo imaging with GFP fusion proteins

1999 ◽  
Vol 112 (1) ◽  
pp. 111-125 ◽  
Author(s):  
M.R. Amieva ◽  
P. Litman ◽  
L. Huang ◽  
E. Ichimaru ◽  
H. Furthmayr
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Fluorescent Protein ◽  
Cultured Cells ◽  
Full Length ◽  
Cell Behavior ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Carboxy Terminal Domain ◽  
Carboxy Terminal

Lamellipodia, filopodia, microspikes and retraction fibers are characteristic features of a dynamic and continuously changing cell surface architecture and moesin, ezrin and radixin are thought to function in these microextensions as reversible links between plasma membrane proteins and actin microfilaments. Full-length and truncated domains of the three proteins were fused to green fluorescent protein (GFP), expressed in NIH3T3 cells, and distribution and behaviour of cells were analysed by using digitally enhanced differential interference contrast (DIC) and fluorescence video microscopy. The amino-terminal (N-)domains of all three proteins localize to the plasma membrane and fluorescence recordings parallel the dynamic changes in cell surface morphology observed by DIC microscopy of cultured cells. Expression of this domain, however, significantly affects cell surface architecture by the formation of abnormally long and fragile filopodia that poorly attach and retract abnormally. Even more striking are abundant irregular, branched and motionless membraneous structures that accumulate during retraction of lamellipodia. These are devoid of actin, endogenous moesin, ezrin and radixin, but contain the GFP-labeled domain. While a large proportion of endogenous proteins can be extracted with non-ionic detergents as in untransfected control cells, >90% of N-moesin and >60% of N-ezrin and N-radixin remain insoluble. The minimal size of the domain of moesin required for membrane localization and change in behavior includes residues 1–320. Deletions of amino acid residues from either end result in diffuse intracellular distribution, but also in normal cell behavior. Expression of GFP-fusions of full-length moesin or its carboxy-terminal domain has no effect on cell behavior during the observation period of 6–8 hours. The data suggest that, in the absence of the carboxy-terminal domain, N-moesin, -ezrin and -radixin interact tightly with the plasma membrane and interfere with normal functions of endogeneous proteins mainly during retraction.

The Amino-Terminal 1−185 Domain of ApoE Promotes the Clearance of Lipoprotein Remnants in Vivo.The Carboxy-Terminal Domain Is Required for Induction of Hyperlipidemia in Normal and ApoE-Deficient Mice†

Biochemistry ◽  
2001 ◽  
Vol 40 (20) ◽  
pp. 6027-6035 ◽  
Author(s):  
Kyriakos E. Kypreos ◽  
Pamela Morani ◽  
Ko Willems van Dijk ◽  
Louis M. Havekes ◽  
Vassilis I. Zannis
Keyword(s):  
Amino Terminal ◽  
Terminal Domain ◽  
Carboxy Terminal Domain ◽  
Carboxy Terminal ◽  
Deficient Mice

scholarly journals A Major Determinant for Membrane Protein Interaction Localizes to the Carboxy-Terminal Domain of the Mouse Coronavirus Nucleocapsid Protein

2005 ◽  
Vol 79 (21) ◽  
pp. 13285-13297 ◽  
Author(s):  
Kelley R. Hurst ◽  
Lili Kuo ◽  
Cheri A. Koetzner ◽  
Rong Ye ◽  
Bilan Hsue ◽  
...  
Keyword(s):  
Viral Envelope ◽  
M Protein ◽  
N Protein ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Dominant Negative Mutation ◽  
Carboxy Terminal Domain ◽  
Domain 3 ◽  
Positive Strand Rna ◽  
Carboxy Terminal

ABSTRACT The two major constituents of coronavirus virions are the membrane (M) and nucleocapsid (N) proteins. The M protein is anchored in the viral envelope by three transmembrane segments flanked by a short amino-terminal ectodomain and a large carboxy-terminal endodomain. The M endodomain interacts with the viral nucleocapsid, which consists of the positive-strand RNA genome helically encapsidated by N protein monomers. In previous work with the coronavirus mouse hepatitis virus (MHV), a highly defective M protein mutant, MΔ2, was constructed. This mutant contained a 2-amino-acid carboxy-terminal truncation of the M protein. Analysis of second-site revertants of MΔ2 revealed mutations in the carboxy-terminal region of the N protein that compensated for the defect in the M protein. To seek further genetic evidence corroborating this interaction, we generated a comprehensive set of clustered charged-to-alanine mutants in the carboxy-terminal domain 3 of N protein. One of these mutants, CCA4, had a highly defective phenotype similar to that of MΔ2. Transfer of the CCA4 mutation into a partially diploid MHV genome showed that CCA4 was a loss-of-function mutation rather than a dominant-negative mutation. Analysis of multiple second-site revertants of CCA4 revealed mutations in both the M protein and the N protein that could compensate for the original lesion in N. These data more precisely define the region of the N protein that interacts with the M protein. Further, we found that fusion of domain 3 of the N protein to the carboxy terminus of a heterologous protein caused it to be incorporated into MHV virions.

scholarly journals Autoantibodies from patients with primary biliary cirrhosis recognize a restricted region within the cytoplasmic tail of nuclear pore membrane glycoprotein Gp210.

1993 ◽  
Vol 178 (6) ◽  
pp. 2237-2242 ◽  
Author(s):  
R E Nickowitz ◽  
H J Worman
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Primary Biliary Cirrhosis ◽  
Antigenic Determinants ◽  
Nuclear Pore ◽  
Biliary Cirrhosis ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Carboxy Terminal ◽  
Amino Terminal Domain

Patients with primary biliary cirrhosis (PBC) frequently have autoantibodies against a 210-kD integral glycoprotein of the nuclear envelope pore membrane. This protein, termed gp210, has a 1,783-amino acid amino-terminal domain located in the perinuclear space, a 20-amino acid transmembrane segment, and a 58-amino acid cytoplasmic carboxy-terminal tail. We now demonstrate that autoantibodies from 25 patients with PBC that recognize gp210 react with the cytoplasmic carboxy-terminal tail while none react with unmodified linear epitopes in the amino-terminal domain. The epitope(s) recognized by autoantibodies from all 25 patients is contained within a stretch of 15 amino acids. The recognized amino acid sequence is homologous to the protein products of the Escherichia coli mutY gene and Salmonella typhimurium mutB gene with an exact identity of six consecutive amino acids, suggesting that anti-gp210 antibodies may arise by molecular mimicry of bacterial antigenic determinants.

p190 RhoGAP, the major RasGAP-associated protein, binds GTP directly

1994 ◽  
Vol 14 (11) ◽  
pp. 7173-7181
Author(s):  
R Foster ◽  
K Q Hu ◽  
D A Shaywitz ◽  
J Settleman
Keyword(s):  
Structural Features ◽  
Cellular Protein ◽  
Small Gtpases ◽  
Sequence Motifs ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Gtp Binding ◽  
Guanine Nucleotide Binding ◽  
Complex Forms ◽  
Carboxy Terminal

In mitogenically stimulated cells, a specific complex forms between the Ras GTPase-activating protein (RasGAP) and the cellular protein p190. We have previously reported that p190 contains a carboxy-terminal domain that functions as a GAP for the Rho family GTPases. Thus, the RasGAP-p190 complex may serve to couple Ras- and Rho-mediated signalling pathways. In addition to its RhoGAP domain, p190 contains an amino-terminal domain that contains sequence motifs found in all known GTPases. Here, we report that p190 binds GTP and GDP through this conserved domain and that the structural requirements for binding are similar to those seen with other GTPases. While the purified protein is unable to hydrolyze GTP, we detect an activity in cell lysates that can promote GTP hydrolysis by p190. A mutated form of p190 that fails to bind nucleotide retains its RasGAP binding and RhoGAP activities, indicating that GTP binding by p190 is not required for these functions. The sequence of p190 in the GTP-binding domain, which shares structural features with both the Ras-like small GTPases and the larger G proteins, suggests that this protein defines a novel class of guanine nucleotide-binding proteins.

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