@article{oai:nagasaki-u.repo.nii.ac.jp:00020752,
 author = {Matsunaga, Hayato and Ueda, Hiroshi},
 issue = {6},
 journal = {Neurochemistry International},
 month = {May},
 note = {It is known that fibroblast growth factor-1 (FGF1) lacking a conventional signal peptide sequence shows non-classical release independent of the endoplasmic reticulum-Golgi system. Recent studies reveal that FGF1 is co-released with S100A13, a Ca2+-binding protein that acts as an extracellular cargo molecule. Although both FGF1 and S100A13 are Cu2+-binding proteins, the role of Cu2+, as well as that of Ca2+, in non-classical release, remains to be clarified. In the present study we examined the requirements of both metal ions for the interaction between these two proteins. The addition of Ca2+ significantly increased the ka value, while decreasing the KD value, for the interaction between Strep-tagII-S100A13 and GST-FGF1; both values were obtained by use of a quartz crystal microbalance, a real-time mass-measuring device. The EC50 of Ca2+ to enhance the interaction was 10.11 μM. Although the addition of Cu2+ alone had no effect, it caused a marked potentiation of the Ca2+-enhanced interaction. The EC50 of Cu2+ for the potentiation was 50.45 nM. On the other hand, the EC50 of Ca2+ and the KD values were decreased from 11.69 to 2.07 μM and 0.75 to 0.38 × 10?7 M, respectively, by the addition of 200 nM Cu2+. The Cu2+-induced potentiation of this interaction was abolished by amlexanox, which inhibits non-classical release of FGF1. All of these findings suggest that synergistic effects of Ca2+ and Cu2+ play a key role in the interaction between FGF1 and S100A13, which is the initial step in non-classical release of FGF1., Neurochemistry International 52(6), pp.1076-1085; 2008},
 pages = {1076--1085},
 title = {Synergistic Ca2+ and Cu2+ requirements of the FGF1-S100A13 interaction measured by quartz crystal microbalance: An initial step in amlexanox-reversible non-classical release of FGF1},
 volume = {52},
 year = {2008}
}