ИСТИНА

Methylglyoxal (MGO) is highly reactive dicarbonyl formed in the course of glucose metabolism. Its concentration is increased under certain pathological conditions, i.e. diabetes or carcinogens is. The data of literature (Sakamoto et al JBC 274, 45770, 2003; Schalwijk et al., FEBS Letters 580,1565, 2006) indicate that HspB1 (Hsp27) is the main protein target of MGO modification. Oya-Ito et al (BBA1812, 769, 2011, J.Cell.Biochem. 99, 279, 2006) claim that MGO-modification affects important properties and chaperone-like activity of HspB1. By using three commercial available monoclonal anti-MGO antibodies we tried to analyze MGO modification of HspB1 in vitro and in HeLa cells. Antibodies of the first type recognized both MGO-modified and unmodified HspB1. Our data indicate that that these antibodies recognize structural epitope that includes Arg188 of HspB1. Two other commercial monoclonal antibodies were also unspecific and interact with many different unmodified proteins in cell lysates. MGO-modification results in formation of a number of different products (different hydroimidazolones, argpyrimidines, carboxymethyllysines and different cross linked products). These products can somehow imitate the structure of unmodified proteins and therefore it is practically impossible to obtain highly specific antibodies by using any protein modified by MGO. Thus, the data of literature require revision and HspB1 cannot be considered as the main target of MGO modification.