Calcium-dependent interaction of S100B with the C-terminal domain of the tumor suppressor p53.
In vitro, the S100B protein interacts with baculovirus recombinant p53 protein and protects p53 from thermal denaturation. This effect is isoform-specific and is not observed with S100A1, S100A6, or calmodulin. Using truncated p53 proteins in the N-terminal (p53(1-320)) and C-terminal (p53(73-393)) domains, we localized the S100B-binding region to the C-terminal region of p53. We have confirmed a calcium-dependent interaction of the S100B with a synthetic peptide corresponding to the C-terminal region of p53 (residues 319-393 in human p53) using plasmon resonance experiments on a BIAcore system. In the presence of calcium, the equilibrium affinity of the S100B for the C-terminal region of p53 immobilized on the sensor chip was 24 +/- 10 nM. To narrow down the region within p53 involved in S100B binding, two synthetic peptides, O1(357-381) (residues 357-381 in mouse p53) and YF-O2(320-346) (residues 320-346 in mouse p53), covering the C-terminal region of p53 were compared for their interaction with purified S100B. Only YF-O2 peptide interacts with S100B with high affinity. The YF-O2 motif is a critical determinant for the thermostability of p53 and also corresponds to a domain responsible for cytoplasmic sequestration of p53. Our results may explain the rescue of nuclear wild type p53 activities by S100B in fibroblast cell lines expressing the temperature-sensitive p53val135 mutant at the nonpermissive temperature.
Delphin
C
C
Département de Biologie Moléculaire et Structurale du Commissariat à Energie Atomique, INSERM Unité 244, 38054 Grenoble, France.
Ronjat
M
M
Deloulme
J C
JC
Garin
G
G
Debussche
L
L
Higashimoto
Y
Y
Sakaguchi
K
K
Baudier
J
J
D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002417:Cattle; D003593:Cytoplasm / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D006358:Hot Temperature; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors / Q000378:metabolism*; D010449:Peptide Mapping; D011485:Protein Binding; D011489:Protein Denaturation; D011994:Recombinant Proteins / Q000378:metabolism; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D013329:Structure-Activity Relationship; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D009414:Nerve Growth Factors; D011994:Recombinant Proteins; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579160:S100B protein, human; C579159:S100b protein, mouse; D016159:Tumor Suppressor Protein p53; D002118:Calcium