S100A5

Case Study 1: Ching Chang Cho, 2016

The human S100 protein family contains small, dimeric and acidic proteins that contain two EF-hand motifs and bind calcium. When S100A5 binds calcium, its conformation changes and promotes interaction with the target protein. The extracellular domain of RAGE (Receptor of Advanced Glycation End products) contain three domains: C1, C2 and V. The RAGE V domain is the target protein of S100A5 that promotes cell survival, growth and differentiation by activating several signaling pathways. Pentamidine is an apoptotic and antiparasitic drug that is used to treat or prevent pneumonia. Here, the researchers found that pentamidine interacts with S100A5 using HSQC titration. They elucidated the interactions of S100A5 with RAGE V domain and pentamidine using fluorescence and NMR spectroscopy. They generated two binary models-the S100A5-RAGE V domain and S100A5-Pentamidine complex-and then observed that the pentamidine and RAGE V domain share a similar binding region in mS100A5. They also used the WST-1 assay to investigate the bioactivity of S100A5, RAGE V domain and pentamidine.

Fig1. Fluorescence emission spectra of RAGE V domain illustrating the changes in the intrinsic tryptophan fluorescence that occur with increasing concentrations of mS100A5 in the micromolar range.

Fig2. SW480 cells were treated with 10 nM mS100A5, 50 nM mS100A5, 100 nM mS100A5, 100 nM mS100A5þ1 mM RAGE V domain, and 100 nM mS100A5 þ1 mM pentamidine.

Case Study 2: B W Schäfer, 2000

S100A5 is a novel member of the EF-hand superfamily of calcium-binding proteins that is poorly characterized at the protein level. Immunohistochemical analysis demonstrates that it is expressed in very restricted regions of the adult brain. Here the researchers characterized the human recombinant S100A5, especially its interaction with Ca(2+), Zn(2+), and Cu(2+). Flow dialysis revealed that the homodimeric S100A5 binds four Ca(2+) ions with strong positive cooperativity and an affinity 20-100-fold higher than the other S100 proteins studied under identical conditions. S100A5 also binds two Zn(2+) ions and four Cu(2+) ions per dimer. Cu(2+) binding strongly impairs the binding of Ca(2+); however, none of these ions change the alpha-helical-rich secondary structure. After covalent labeling of an exposed thiol with 2-(4'-(iodoacetamide)anilino)-naphthalene-6-sulfonic acid, binding of Cu(2+), but not of Ca(2+) or Zn(2+), strongly decreased its fluorescence.

Fig3. expression and purification of human recombinant S100A5.

Fig4. Mass spectrum of rat S100A5 isolated from rat brain tissue.

S100A5 involved in several pathways and played different roles in them. We selected most pathways S100A5 participated on our site, such as , which may be useful for your reference. Also, other proteins which involved in the same pathway with S100A5 were listed below. Creative BioMart supplied nearly all the proteins listed, you can search them on our site.

S100A5 has several biochemical functions, for example, calcium ion binding, copper ion binding, protein homodimerization activity. Some of the functions are cooperated with other proteins, some of the functions could acted by S100A5 itself. We selected most functions S100A5 had, and list some proteins which have the same functions with S100A5. You can find most of the proteins on our site.

S100A5 has direct interactions with proteins and molecules. Those interactions were detected by several methods such as yeast two hybrid, co-IP, pull-down and so on. We selected proteins and molecules interacted with S100A5 here. Most of them are supplied by our site. Hope this information will be useful for your research of S100A5.

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