scholarly journals Multiple Sites of Contact between the Carboxyl-terminal Binding Domain of PTHrP-(1–36) Analogs and the Amino-terminal Extracellular Domain of the PTH/PTHrP Receptor Identified by Photoaffinity Cross-linking

2001 ◽  
Vol 276 (31) ◽  
pp. 28650-28658 ◽  
Author(s):  
Robert C. Gensure ◽  
Thomas J. Gardella ◽  
Harald Jüppner
Keyword(s):  
Extracellular Domain ◽  
Binding Domain ◽  
Cross Linking ◽  
Amino Terminal ◽  
Carboxyl Terminal ◽  
Pthrp Receptor

scholarly journals The Ubiquitin-associated Domain of hPLIC-2 Interacts with the Proteasome

2003 ◽  
Vol 14 (9) ◽  
pp. 3868-3875 ◽  
Author(s):  
Maurits F. Kleijnen ◽  
Rodolfo M. Alarcón ◽  
Peter M. Howley
Keyword(s):  
Proteasomal Degradation ◽  
Binding Domain ◽  
Full Length ◽  
Degradation Pathways ◽  
Wild Type ◽  
Amino Terminal ◽  
Uba Domain ◽  
Carboxyl Terminal ◽  
Protein Ligases

The ubiquitin-like hPLIC proteins can associate with proteasomes, and hPLIC overexpression can specifically interfere with ubiquitin-mediated proteolysis ( Kleijnen et al., 2000 ). Because the hPLIC proteins can also interact with certain E3 ubiquitin protein ligases, they may provide a link between the ubiquitination and proteasomal degradation machineries. The amino-terminal ubiquitin-like (ubl) domain is a proteasome-binding domain. Herein, we report that there is a second proteasome-binding domain in hPLIC-2: the carboxyl-terminal ubiquitin-associated (uba) domain. Coimmunoprecipitation experiments of wild-type and mutant hPLIC proteins revealed that the ubl and uba domains each contribute independently to hPLIC-2–proteasome binding. There is specificity for the interaction of the hPLIC-2 uba domain with proteasomes, because uba domains from several other proteins failed to bind proteasomes. Furthermore, the binding of uba domains to polyubiquitinated proteins does not seem to be sufficient for the proteasome binding. Finally, the uba domain is necessary for the ability of full-length hPLIC-2 to interfere with the ubiquitin-mediated proteolysis of p53. The PLIC uba domain has been reported to bind and affect the functions of proteins such as GABAAreceptor and presenilins. It is possible that the function of these proteins may be regulated or mediated through proteasomal degradation pathways.

scholarly journals Platelet thrombospondin mediates attachment and spreading of human melanoma cells.

1987 ◽  
Vol 104 (1) ◽  
pp. 131-139 ◽  
Author(s):  
D D Roberts ◽  
J A Sherwood ◽  
V Ginsburg
Keyword(s):  
Monoclonal Antibodies ◽  
Cell Attachment ◽  
Melanoma Cells ◽  
Binding Domain ◽  
Heparin Binding ◽  
Amino Terminal ◽  
Sulfated Fucan ◽  
Heparin Binding Domain ◽  
Carboxyl Terminal ◽  
Inhibition Studies

Human platelet thrombospondin adsorbed on plastic promotes attachment and spreading of human G361 melanoma cells. Attachment is rapid, and spreading is maximal by 90 min with 60-90% of the attached cells spread. In contrast, thrombospondin promotes attachment but not spreading of human C32 melanoma cells, which attach and spread only on laminin substrates. The specificity of these interactions and the regions of the thrombospondin molecule involved in attachment and spreading were examined using proteolytic fragments of thrombospondin and by inhibition studies. The sulfated fucan, fucoidan, and monoclonal antibody A2.5, which is directed against the heparin-binding domain of thrombospondin, selectively inhibit spreading but only weakly inhibit attachment. Monoclonal antibodies against some other domains of thrombospondin, however, are potent inhibitors of attachment. The amino-terminal heparin-binding domain of thrombospondin does not promote attachment. Large fragments lacking the heparin-binding domain support attachment but not spreading of G361 cells. Attachment activity is lost following removal of the 18-kD carboxyl-terminal domain. These results suggest that at least two melanoma ligands are involved in cell attachment and spreading on thrombospondin. The carboxyl-terminal region and perhaps other regions of the molecule bind to receptor(s) on the melanoma surface that promote initial attachment but not cell spreading. Interaction of the heparin-binding domain with sulfated glycoconjugates on melanoma surface proteoglycans and/or sulfated glycolipids mediates spreading. Monoclonal antibodies A2.5 and C6.7 also reverse spreading of G361 cells growing on glass culture substrates, suggesting that binding to thrombospondin mediates attachment of these melanoma cells in culture.

scholarly journals Sequence of Events Underlying the Allosteric Transition of Rod Cyclic Nucleotide–gated Channels

1999 ◽  
Vol 113 (5) ◽  
pp. 621-640 ◽  
Author(s):  
Elizabeth R. Sunderman ◽  
William N. Zagotta
Keyword(s):  
Amino Acid ◽  
Cyclic Nucleotide ◽  
Binding Domain ◽  
Terminal Region ◽  
Allosteric Transition ◽  
Amino Terminal ◽  
Sequence Of Events ◽  
Carboxyl Terminal ◽  
Purine Ring ◽  
Closing Rate

Activation of cyclic nucleotide–gated (CNG) ion channels involves a conformational change in the channel protein referred to as the allosteric transition. The amino terminal region and the carboxyl terminal cyclic nucleotide–binding domain of CNG channels have been shown to be involved in the allosteric transition, but the sequence of molecular events occurring during the allosteric transition is unknown. We recorded single-channel currents from bovine rod CNG channels in which mutations had been introduced in the binding domain at position 604 and/or the rat olfactory CNG channel amino terminal region had been substituted for the bovine rod amino terminal region. Using a hidden Markov modeling approach, we analyzed the kinetics of these channels activated by saturating concentrations of cGMP, cIMP, and cAMP. We used thermodynamic mutant cycles to reveal an interaction during the allosteric transition between the purine ring of the cyclic nucleotides and the amino acid at position 604 in the binding site. We found that mutations at position 604 in the binding domain alter both the opening and closing rate constants for the allosteric transition, indicating that the interactions between the cyclic nucleotide and this amino acid are partially formed at the time of the transition state. In contrast, the amino terminal region affects primarily the closing rate constant for the allosteric transition, suggesting that the state-dependent stabilizing interactions between amino and carboxyl terminal regions are not formed at the time of the transition state for the allosteric transition. We propose that the sequence of events that occurs during the allosteric transition involves the formation of stabilizing interactions between the purine ring of the cyclic nucleotide and the amino acid at position 604 in the binding domain followed by the formation of stabilizing interdomain interactions.

scholarly journals Independent and Interchangeable Multimerization Domains of the AbrB, Abh, and SpoVT Global Regulatory Proteins

2005 ◽  
Vol 187 (18) ◽  
pp. 6354-6362 ◽  
Author(s):  
Fude Yao ◽  
Mark A. Strauch
Keyword(s):  
Dna Binding ◽  
Binding Domain ◽  
Chimeric Proteins ◽  
Dna Binding Domain ◽  
Global Regulators ◽  
Amino Terminal ◽  
Sequence Homologies ◽  
Carboxyl Terminal ◽  
Paralogous Proteins

ABSTRACT The global regulators AbrB, Abh, and SpoVT are paralogous proteins showing their most extensive sequence homologies in the DNA-binding amino-terminal regions (about 50 residues). The carboxyl-terminal portion of AbrB has been hypothesized to be a multimerization domain with little if any role in DNA-binding recognition or specificity. To investigate the multimerization potentials of the carboxyl-terminal portions of AbrB, Abh, and SpoVT we utilized an in vivo multimerization assay system based upon fusion of the domains to the DNA binding domain of the λ cI repressor protein. The results indicate that the N and C domains of all three paralogues are independent dimerization modules and that the intact Abh and SpoVT proteins are most probably tetramers. Chimeric proteins consisting of the AbrB N-terminal DNA-binding domain fused to the C domain of either Abh or SpoVT are indistinguishable from wild-type AbrB in their ability to regulate an AbrB target promoter in vivo.

scholarly journals The crystal structure of the global anaerobic transcriptional regulator FNR explains its extremely fine-tuned monomer-dimer equilibrium

2015 ◽  
Vol 1 (11) ◽  
pp. e1501086 ◽  
Author(s):  
Anne Volbeda ◽  
Claudine Darnault ◽  
Oriane Renoux ◽  
Yvain Nicolet ◽  
Juan C. Fontecilla-Camps
Keyword(s):  
Crystal Structure ◽  
Coiled Coil ◽  
Binding Domain ◽  
Salt Bridges ◽  
Dimer Interface ◽  
Amino Terminal ◽  
Oxygen Sensitive ◽  
Aliivibrio Fischeri ◽  
Carboxyl Terminal ◽  
Terminal Cluster

The structure of the dimeric holo–fumarate and nitrate reduction regulator (FNR) from Aliivibrio fischeri has been solved at 2.65 Å resolution. FNR globally controls the transition between anaerobic and aerobic respiration in facultative anaerobes through the assembly/degradation of its oxygen-sensitive [4Fe-4S] cluster. In the absence of O2, FNR forms a dimer and specifically binds to DNA, whereas in its presence, the cluster is degraded causing FNR monomerization and DNA dissociation. We have used our crystal structure and the information previously gathered from numerous FNR variants to propose that this process is governed by extremely fine-tuned interactions, mediated by two salt bridges near the amino-terminal cluster-binding domain and an “imperfect” coiled-coil dimer interface. [4Fe-4S] to [2Fe-2S] cluster degradation propagates a conformational signal that indirectly causes monomerization by disrupting the first of these interactions and unleashing the “unzipping” of the FNR dimer in the direction of the carboxyl-terminal DNA binding domain.

Diversity of Primary Structures of the Carboxy-terminal Regions of Mammalian Fibrinogen Aα-Chains

1993 ◽  
Vol 69 (04) ◽  
pp. 351-360 ◽  
Author(s):  
Masahiro Murakawa ◽  
Takashi Okamura ◽  
Takumi Kamura ◽  
Tsunefumi Shibuya ◽  
Mine Harada ◽  
...  
Keyword(s):  
Amino Acid ◽  
Rhesus Monkey ◽  
Syrian Hamster ◽  
Tandem Repeats ◽  
Mammalian Species ◽  
Amino Acid Sequences ◽  
Point Of View ◽  
Cross Linking ◽  
Amino Terminal ◽  
Rgd Sequence

SummaryThe partial amino acid sequences of fibrinogen Aα-chains from five mammalian species have been inferred by means of the polymerase chain reaction (PCR). From the genomic DNA of the rhesus monkey, pig, dog, mouse and Syrian hamster, the DNA fragments coding for α-C domains in the Aα-chains were amplified and sequenced. In all species examined, four cysteine residues were always conserved at the homologous positions. The carboxy- and amino-terminal portions of the α-C domains showed a considerable homology among the species. However, the sizes of the middle portions, which corresponded to the internal repeat structures, showed an apparent variability because of several insertions and/or deletions. In the rhesus monkey, pig, mouse and Syrian hamster, 13 amino acid tandem repeats fundamentally similar to those in humans and the rat were identified. In the dog, however, tandem repeats were found to consist of 18 amino acids, suggesting an independent multiplication of the canine repeats. The sites of the α-chain cross-linking acceptor and α2-plasmin inhibitor cross-linking donor were not always evolutionally conserved. The arginyl-glycyl-aspartic acid (RGD) sequence was not found in the amplified region of either the rhesus monkey or the pig. In the canine α-C domain, two RGD sequences were identified at the homologous positions to both rat and human RGD S. In the Syrian hamster, a single RGD sequence was found at the same position to that of the rat. Triplication of the RGD sequences was seen in the murine fibrinogen α-C domain around the homologous site to the rat RGDS sequence. These findings are of some interest from the point of view of structure-function and evolutionary relationships in the mammalian fibrinogen Aα-chains.

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