Telomere repeat binding factor (TRF) family proteins are important for the regulation of telomere stability. The two related human TRF proteins hTRF1 and hTRF2 form homodimers and bind directly to telomeric TTAGGG repeats via the myb DNA binding domain pfam00249 at the carboxy terminus. TRF1 is implicated in telomere length regulation and TRF2 in telomere protection. Other telomere complex associated proteins are recruited through their interaction with either TRF1 or TRF2. The fission yeast protein Taz1p (telomere-associated in Schizosaccharomyces pombe) has similarity to both hTRF1 and hTRF2 and may perform the dual functions of TRF1 and TRF2 at fission yeast telomeres. This domain is composed of multiple alpha helices arranged in a solenoid conformation similar to TPR repeats. The fungal members have now also been found to carry two double strand telomeric repeat binding factors.