Telomere Maintenance 2 (TELO2)

Unlike yeast Tel2, human TELO2 does not function in telomere maintenance, but has a critical role in checkpoint responses to cellular stress. human TEL2 appeared to have no function in telomere maintenance. Conditional deletion of Tel2 from mouse embryonic fibroblasts compromised their response to ionizing and ultraviolet radiation by diminishing activation of checkpoint kinases and their downstream effectors. While Tel2 deletion did not alter PIKK mRNA levels, in vivo pulse labeling experiments showed that Tel2 controlled the stability of Atm and Mtor. Each of the PIKK family members associated with mouse and human TEL2 in vivo, and in vitro experiments showed that TEL2 bound to part of the HEAT repeat segments of human ATM and rat Mtor.