Identification of intracellular target proteins of the calcium-signaling protein S100A12.

摘要: In this report, we have focused our attention on identifying intracellular mammalian proteins that bind S100A12 in a Ca2+-dependent manner. Using affinity chromatography, identified cytosolic NADP+-dependent isocitrate dehydrogenase (IDH), fructose-1,6-bisphosphate aldolase A (aldolase), glyceraldehyde-3-phosphate dehydrogenese (GAPDH), annexin V, S100A9, and itself as S100A12-binding proteins. Immunoprecipitation experiments indicated the formation of stable complexes between IDH, aldolase, GAPDH, V S100A9 vivo. Surface plasmon resonance analysis showed binding to S100A12, was strictly Ca2+-dependent, whereas GAPDH IDH only weakly Ca2+-dependent. To localize site interaction, examined series C-terminal truncation mutants S100A12-immobilized sensor chip. The results is located at C-terminus (residues 87–92). However, cross-linking with residues 87–92 were not essential for dimerization. Thus, interaction or immobilized should be viewed typical S100 homo- heterodimerization model. chromatography revealed 75–92 are necessary V. analyze functional properties studied its action protein folding reactions vitro. thermal aggregation facilitated by absence Ca2+, presence Ca2+ suppressed less than 50%. These suggest may chaperone/antichaperone-like function which