[Screening of proteins interacting with tTG in HeLa cells].

Tissue transglutaminase(tTG) belongs to a class of transglutaminase family which is up-regulated in almost all cells apoptosis and is thought to be closely related to cell apoptosis. To investigate the mechanism of tTG in cell apoptosis, yeast two hybrid system was used to screen HeLa cDNA library. One of the 17 positive clones we have obtained encoded the glutamine-rich carboxyl terminus of TIAR, and this interaction between tTG and TIAR, which was finely regulated by Ca(2+), was proved in vitro by GST pull-down. These findings suggest that tTG might affect the function of TIAR by a calcium-dependent posttranslational modification and the interaction might possibly be involved in the regulation of cell apoptosis.