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Identification of Effector Binding Sites on S100β: Studies with Guanylate Cyclase and p80, a Retinal Phosphoprotein
- Source :
- Biochemistry. 37:10701-10708
- Publication Year :
- 1998
- Publisher :
- American Chemical Society (ACS), 1998.
-
Abstract
- S100 beta is a calcium-binding protein, which regulates the activities of several enzymes and inhibits the phosphorylation of a variety of protein kinase C substrates in a calcium-dependent manner. The protein was recently found to activate a retinal membrane guanylate cyclase, and in this paper, we report that it inhibits the phosphorylation of an 80 kDa retinal protein (p80). Structurally, S100 beta consists of two EF-hands connected by a hinge region. In view of its small size, wide distribution in a variety of tissues, and regulation of many different proteins, it is of interest to identify the sites on the protein that interact with the effectors, and to determine if the same sites are responsible for interaction with different effectors. We addressed these questions with the use of synthetic peptides with sequences corresponding to different regions of S100 beta and testing their effects on the protein's activation of guanylate cyclase, and inhibition of p80 phosphorylation. Peptides with sequences corresponding to effector interaction sites were anticipated to either block or simulate the effects of S100 beta. The results show that two regions of S100 beta interact with effectors: the C-terminal region of Thr81-Glu91 and the hinge region of Leu32-Leu40. The synthetic peptide containing the latter sequence blocked the S100 beta activation of guanylate cyclase and inhibition of p80 phosphorylation, while the peptide containing the former sequence blocked cyclase activation and simulated S100 beta in inhibiting p80 phosphorylation. By determining the effects of including or excluding dithiothreitol in the assays, we observed that the cysteine residue in the C-terminal region of S100 beta (Cys84) participates in the regulation of guanylate cyclase but not of p80 phosphorylation. We conclude from these results that the C-terminal and hinge regions of S100 beta are important in the regulation of effector proteins and that Cys84 is essential for interaction with only specific effectors.
- Subjects :
- GUCY1B3
Molecular Sequence Data
S100 Calcium Binding Protein beta Subunit
Biochemistry
Cyclase
Retina
Animals
Amino Acid Sequence
Nerve Growth Factors
Phosphorylation
Eye Proteins
Myristoylated Alanine-Rich C Kinase Substrate
Protein Kinase C
GUCY1A2
Binding Sites
Dose-Response Relationship, Drug
Chemistry
Calcium-Binding Proteins
S100 Proteins
GUCY1A3
Intracellular Signaling Peptides and Proteins
Membrane Proteins
Proteins
Guanylate cyclase 2C
Phosphoproteins
Rod Cell Outer Segment
NPR1
Peptide Fragments
Cell biology
Enzyme Activation
Molecular Weight
Guanylate Cyclase
GUCY2D
Cattle
Subjects
Details
- ISSN :
- 15204995 and 00062960
- Volume :
- 37
- Database :
- OpenAIRE
- Journal :
- Biochemistry
- Accession number :
- edsair.doi.dedup.....d822431986a9ea74669c0b0d64a5c4eb