The ability of APC to bind β-catenin has been classically considered to be an integral part of the protein's mechanistic function in the destruction complex, along with binding to Axin through the SAMP repeats.[16] These models have been substantiated by observations that common APC loss of function mutations in the mutation cluster region often remove several β-catenin binding sites and SAMP repeats. However, recent evidence from Yamulla and colleagues have directly tested those models and imply that APC's core mechanistic functions may not require direct binding to β-catenin, but necessitate interactions with Axin.[17] The researchers hypothesized that APC's many β-catenin binding site increase the protein's efficiency at destroying β-catenin, yet are not absolutely necessary for the protein's mechanistic function. Further research is clearly necessary to elucidate the precise mechanistic function of APC in the destruction complex.