Abstract
The rat synapse associated protein SAP90 is a member of a superfamily of potential guanylate kinases localized at cell-cell contact sites. This superfamily includes the synapse associated protein SAP97, a close relative of SAP90, the Drosophila tumor suppressor gene product dlg-Ap, the mammalian zonula occludens proteins ZO-1 and ZO-2 and the erythrocyte protein p55. Here we show that SAP90 specifically binds GMP in the micromolar range while binding to ATP, GDP and ADP is at a much lower affinity (10-25 mM), whether or not binding is detected for other guanine and adenine nucleotides. No guanylate kinase activity of SAP90 was detected under our experimental conditions. The importance of the GMP binding capacity per se and an evolutionary role for conserving of the guanylate kinase domain in this superfamily are discussed.
| Original language | English |
|---|---|
| Pages (from-to) | 159-163 |
| Number of pages | 5 |
| Journal | FEBS Letters |
| Volume | 359 |
| Issue number | 2-3 |
| DOIs | |
| State | Published - 13 Feb 1995 |
Bibliographical note
Funding Information:Acknowledgments: We would like to thank Dr. Klaus Hermann for his help in analyzing the GK activity. This work was supported by a Feodor-Lynen-fellowship from the Alexander von Humboldt Stiftung (to U.K.), by the Federal Government of Germany (Bundesminis-terium fuer Forschung und Technologie), by the Israeli Academy of Science (Grant 152193 to M. L.) and the Ministry for Sciences and Arts (4363-1-93 to M.L.).
Keywords
- Dlg-A
- Guanylate kinase
- Nucleotide binding
- Synaptic protein