Specificity and Zn2+ Enhancement of the S100B Binding Epitope TRTK-12

Barber, Kathryn R.; McClintock, Kimberly A.; Jamieson, Gordon A.; Dimlich, Ruth V.W.; Shaw, Gary S.

doi:10.1074/jbc.274.3.1502

Cited by 50 publications

(61 citation statements)

References 48 publications

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“…2C). TRTK-12 showed a similar affinity for S100B with K d values of 0.2-1 M in previous studies (20,21). Experiments performed in the absence of Ca 2ϩ showed no significant binding of ␣C28 peptide to S100B, at concentrations of S100B up to 42 M (data not shown), consistent with previous results for the TRTK-12 peptide (20,21).…”

Section: Resultssupporting

confidence: 80%

“…2B). Similar results were observed with the TRTK-12 peptide in previous studies (20,21). The blue shift reflects a change in the environment of the tryptophan residue to a less polar one, in agreement with the hydrophobic nature of the binding interaction between TRTK-12 and S100B in the NMR solution structure (22).…”

Section: Resultssupporting

confidence: 78%

“…Previous studies had shown that a shorter peptide, TRTK-12 (CP␣ residues Thr 265 -Ser 276 ), binds tightly (20,21). We measured binding of a synthetic ␣C28 peptide to recombinant S100B (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The C terminus of CP␣ appears to be folded down onto the surface of the protein and relatively immobile. We were able to test this aspect of the model for the CP␣ subunit because of previous results showing that S100B can bind to a peptide derived from the C terminus of CP␣ (20,21). We found that S100B was able to bind the isolated C-terminal 28 amino acids of CP␣, with K d values in the 0.4 -1 M range.…”

Section: Discussionmentioning

confidence: 99%

“…The C-terminal region of human CP␣ (both ␣1 and ␣2 isoforms have identical sequences over the last 52 C-terminal residues) contains this consensus sequence. A 12-residue peptide termed TRTK-12 (TRTKIDWNKILS, corresponding to residues Thr 265 -Ser 276 of CP␣) was found to bind tightly (K d ϳ0.2-1 M) to S100B (20,21). In an NMR solution structure of TRTK-12 bound to S100B, hydrophobic residues of an amphipathic ␣-helix in TRTK-12 make contact with a hydrophobic binding pocket in S100B (22).…”

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confidence: 99%

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Capping Protein Binding to S100B

Wear

Cooper

2004

Journal of Biological Chemistry

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S100B binds tightly to a 12-amino acid peptide derived from heterodimeric capping protein. In native intact capping protein, this sequence is in the C terminus of the ␣-subunit, which is important for capping the actin filament. This C-terminal region is proposed to act as a flexible "tentacle," extending away from the body of capping protein in order to bind actin. To this hypothesis, we analyzed the interaction between S100B and capping protein in solution. The C-terminal 28 amino acids of the ␣-subunit, the proposed tentacle, bound to S100B as a free synthetic peptide or a glutathione S-transferase fusion (K d ϳ0.4 -1 M). In contrast, S100B did not bind to whole native capping protein or functionally affect its capping activity. S100B does not bind, with any significant affinity, to the proposed ␣-tentacle sequence of whole native capping protein in solution. In the NMR structure of S100B complexed with the ␣-subunit-derived 12-amino acid peptide, the hydrophobic side of a short ␣-helix in the peptide, containing an important tryptophan residue, contacts S100B. In the x-ray structure of native capping protein, the corresponding sequence of the ␣-subunit C terminus, including Trp 271 , interacts closely with the body of the protein. Therefore, our results suggest the ␣-subunit C terminus is not mobile as predicted by the tentacle model. Addition of nonionic detergent allowed whole capping protein to bind weakly to S100B, indicating that the ␣-subunit C terminus can be mobilized from the surface of the capping protein molecule, presumably by weakening the hydrophobic binding at the contact site.Capping protein (CP) 1 is an ␣/␤ heterodimer that tightly caps (K d ϳ0.1-1 nM) the barbed end of the actin filament, preventing actin subunit addition and loss (reviewed in Ref. 1). CP is important for actin assembly and actin-based motility in vivo in Dictyostelium (2), cultured mammalian cells, 2 and striated muscle (4 -7). In Drosophila, CP is essential for early development, morphogenesis, and actin organization (8, 9). CP is also an essential component of the dendritic nucleation model to account for actin polymerization and protrusion at the leading edge of cells (reviewed in Ref. 10).The x-ray crystal structure of CP inspired a model where the C termini (ϳ30 amino acids) of the ␣-and ␤-subunits of CP are mobile extensions, "tentacles," and these regions are responsible for high affinity binding to, and functional capping of, the barbed end (11). We tested one feature of the tentacle model with recombinant mutant chicken (12) and budding yeast CPs (13). Loss of both tentacles causes a complete loss of capping activity, with the ␣-tentacle contributing much more to capping affinity and kinetics. Loss of the ␣-tentacle reduces the capping affinity by 5,000-fold and the capping on-rate by 20-fold in chicken CP (12). In contrast, removal of the ␤-tentacle reduced the affinity by only 300-fold with no effect on the capping on-rate (12). Qualitatively similar results were observed with budding yeast CP (13). Furthermore,...

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Section: Resultssupporting

confidence: 80%

Section: Resultssupporting

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Capping Protein Binding to S100B

Wear

Cooper

2004

Journal of Biological Chemistry

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Molecular mechanisms of S100‐target protein interactions

Zimmer

Sadosky

Weber

2003

Microscopy Res & Technique

142

124

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S100 proteins have no known enzymatic activity and exert their intracellular effects via interaction with and regulation of the activity of other proteins, termed target proteins, in both a Ca(2+)-dependent and Ca(2+)-independent manner. Structural studies have identified the linker region between the two EF-hand Ca(2+) binding domains and the C-terminus as Ca(2+)-dependent target protein binding sites in several S100 family members. In fact, C-terminal aromatic residues are obligatory for interaction of S100A1 with several of its Ca(2+)-dependent target proteins. Pharmacological studies suggest the presence of additional Ca(2+)-dependent binding motifs on some family members. A minimum of seven family members interact with and regulate the activity of aldolase A in a Ca(2+)-independent manner. In the case of S100A1, Ca(2+)-independent target protein interactions utilize a binding motif distinct from the C-terminal Ca(2+)-dependent target protein binding site. Several studies suggest that ionic interactions participate in the interaction of S100 family members with Ca(2+)-independent target proteins. While some target proteins are activated by multiple family members, other target proteins exhibit family member-specific activation, i.e., they are activated by a single family member. As predicted, family member specific interactions appear to be mediated by regions that exhibit the most divergence in amino acid sequence among family members, the linker or "hinge" region and the C terminus. Further specificity in S100-target protein interactions may arise from the different biochemical/biophysical properties of the individual family members, including affinity for metal ions (Ca(2+), Zn(2+), and Cu(2+)), oligomerization properties, heterodimerization, post-translational modifications, and lipid-binding. Delineation of the structural motifs that mediate S100-target protein interactions and determination of the in vivo relevance of these interactions are needed to fully understand the role of S100 proteins in normal and diseased cells.

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Monitoring of S100 homodimerization and heterodimeric interactions by the yeast two‐hybrid system

Deloulme

Gentil

Baudier

2003

Microscopy Res & Technique

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The S100 family consists of 19 members, which function as transducers of calcium signals in a tissue-specific manner. Upon calcium binding, the conformation of many S100 proteins changes dramatically. Several hydrophobic residues are exposed, allowing the S100 proteins to interact with their target proteins, and thereby to transduce calcium signals into specific biological responses. To further elucidate the exact contribution of the S100 calciproteins in the calcium signalling pathways, several groups have applied the yeast two-hybrid technology to identify putative target proteins for the various S100 calciproteins. Two-hybrid large screens using S100 proteins as baits have confirmed the biochemical and structural feature of S100, which enable them to form homodimers and the ability of some members to form specific heterodimers in vivo. Yeast two-hybrid investigations have allowed the identification of conserved hydrophobic residues and domains that are crucial for the stabilization of S100 homo- and heterodimers. Furthermore, this method clearly underlines that the homo- and heterodimerization mechanisms differ among the members of the S100 family. However, several lines of evidence strongly suggest that two-hybrid methodology is limited to the analysis of interactions that are calcium-independent, since no target proteins other than S100 family members themselves have been detected with this methodology.

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Specificity and Zn2+ Enhancement of the S100B Binding Epitope TRTK-12

Cited by 50 publications

References 48 publications

Capping Protein Binding to S100B

Capping Protein Binding to S100B

Molecular mechanisms of S100‐target protein interactions

Monitoring of S100 homodimerization and heterodimeric interactions by the yeast two‐hybrid system

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