Disease relevance of S100a1

• S100B is detected in the outer limiting membrane, fine cell processes in the outer nuclear layer and the outer plexiform layer, cell bodies in the inner nuclear layer and the ganglion cell layer, and the inner limiting membrane, whereas S100A1 has a more discrete distribution [1].
• In the present work we tested S100A1 and S100B for their ability to cause microtubule and/or intermediate filament disassembly in situ using triton-cytoskeletons obtained from U251 glioma cells and rat L6 myoblasts [2].
• Molecular cloning and expression in Escherichia coli of a gene coding for bovine S100A1 protein and its Glu32-->Gln and Glu73-->Gln mutants [3].

High impact information on S100a1

• Thus, this S100A1-S100B protein-mediated calcium-modulated signal transduction mechanism is novel [4].
• Comparison with the fluorescence spectrum of the bovine brain S100-a' protein (alpha'beta), which contains a tryptophan residue in the alpha' subunit, enables us to demonstrate that the recent report describing an abnormal fluorescence spectrum for the bovine brain S100-b protein may result from a contamination of the S100-b by the S100-a' protein [5].
• Effects of S100A1 and S100B on microtubule stability. An in vitro study using triton-cytoskeletons from astrocyte and myoblast cell lines [2].
• S100B and S100A1 also stimulate a membrane-bound guanylate cyclase activity in photoreceptor cell bodies and Muller cells, but their effect appears independent of the light- or dark-adapted state of the retina and is observed at relatively high Ca2+ concentrations [1].
• S100B and S100A1 proteins in bovine retina:their calcium-dependent stimulation of a membrane-bound guanylate cyclase activity as investigated by ultracytochemistry [1].

Biological context of S100a1

• S100A1 is a typical representative of a group of EF-hand calcium-binding proteins known as the S100 family [6].
• Injection of S100A1 mimicked the effects of S100B-s-s on discharge activity and action potentials [7].
• The Ca2(+)-binding proteins of the EF-hand type, S100B and S100A1, were detected in the outer segment of bovine retina photoreceptors where they are localized to disc membranes, as investigated by immunofluorescence and immunogold cytochemistry [1].
• Differences in the binding sites of S100A1 to antiallergic drugs suggest that the regulatory functions of S100 proteins may exist in several regions [8].
• Mutagenesis study showed that amino acid residues 76-85 in S100A1 are necessary for its binding to Olopatadine [8].

Anatomical context of S100a1

• Molecular characterization of S100A1-S100B protein in retina and its activation mechanism of bovine photoreceptor guanylate cyclase [4].
• S100A1 and S100B are members of a multigenic family of Ca(2+)-binding proteins of the EF-hand type highly abundant in astrocyte and striated muscle cells that have been implicated in the Ca(2+)-dependent regulation of several intracellular activities including the assembly and disassembly of microtubules and type III intermediate filaments [2].
• Using confocal microscopy and monoclonal antibodies, we demonstrated that only one of these isoforms, S100A1, was autoexpressed in more than 50% of the PC12 cells analysed [9].

Associations of S100a1 with chemical compounds

• Interaction of S100 proteins with the antiallergic drugs, olopatadine, amlexanox, and cromolyn: identification of putative drug binding sites on S100A1 protein [8].

Other interactions of S100a1

• Examples of applications of the DQ-HN[CACB] and DQ-HN(CO)[CACB] experiments are presented, employing the 2D Reduced Dimensionality approach for 13C, 15N-labeled ubiquitin, and the 3D acquisition for 13C, 15N-double labeled Ca2+ -binding bovine S100A1 protein in the apo state (21 kDa) with overall correlation time of 8.1 ns [10].

Analytical, diagnostic and therapeutic context of S100a1

• In this study, we further investigated the effects of S100 (S100B and S100A1) on electrical discharge activity and membrane currents of Helix neurons, using current- and voltage-clamp techniques [7].

References