TI - Post-translational modification of Rad52 requires its C terminus . AB - A key function of the C-terminal domain of Rad52 involves its interaction with Rad51 , since the gamma-ray sensitivity of a C-terminal RAD52 truncation , rad52-327Delta ( 327Delta ) , can be partially suppressed by overexpression of Rad51 ( 48,49 ) . Surprisingly , only two Rad52 protein bands were observed in a 327Delta mutant strain at any point in the cell cycle (Figure 5D) . These truncated bands likely correspond to the 54 and 57 kDa bands seen in wild-type cells . This result suggests that the C terminus of Rad52 is phosphorylaTED , or alternatively , that Rad52 PHOSphorylation requires sequences in the C terminus . Since the Rad51 interaction domain resides in the C terminus , we tested whether this interaction is required for Rad52 PHOSphorylation by examining Rad52 protein from rad52-409-412Delta (409-412Delta) , which has a four-amino acid deletion within the C-terminal domain of Rad52 that ablates its interaction with Rad51 ( 50 ) . In the 409-412Delta strain , the protein band pattern is identical to wild-type . This result shows that the Rad52-Rad51 interaction is not required for PHOSphorylation ( Figure 5E ) .