| Using CacyBP / SIP affinity chromatography , we found that S100B from the brain extract binds to CacyBP / SIP in a Ca2+ dependent manner . ^^^ Using a nitrocellulose overlay assay with 125I CacyBP / SIP and CacyBP / SIP affinity chromatography , we found that this protein binds purified S100A1 , S100A6 , S100A12 , S100B , and S100P but not S100A4 , calbindin D ( 9k ) , parvalbumin , and calmodulin . ^^^ Co immunoprecipitation of CacyBP / SIP with S100B from brain and with S100A6 from Ehrlich ascites tumor cells suggests that these interactions are physiologically relevant and that the ubiquitinylation complex involving CacyBP / SIP might be regulated by S 100 proteins . . ^^^ |