TRF1 is degraded by ubiquitin-mediated proteolysis after release from telomeres.
Mammalian telomeres are coated by the sequence-specific, DNA-binding protein, TRF1, a negative regulator of telomere length. Previous results showed that ADP-ribosylation of TRF1 by tankyrase 1 released TRF1 from telomeres and promoted telomere elongation. We now show that loss of TRF1 from telomeres results in ubiquitination and degradation of TRF1 by the proteasome and that degradation is required to keep TRF1 off telomeres. Ubiquitination of TRF1 is regulated by its telomere-binding status; only the telomere-unbound form of TRF1 is ubiquitinated. Our findings suggest a novel mechanism of sequential post translational modification of TRF1 (ADP-ribosylation and ubiquitination) for regulating access of telomerase to telomeres.
Chang
William
W
Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York 10016, USA.
Dynek
Jasmin N
JN
Smith
Susan
S
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D010450:Endopeptidases / Q000378:metabolism; D008322:Mammals; D011994:Recombinant Proteins / Q000378:metabolism; D016615:Telomere / Q000235:genetics*; D035321:Telomeric Repeat Binding Protein 1 / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism*
D011994:Recombinant Proteins; D035321:Telomeric Repeat Binding Protein 1; D025801:Ubiquitin; D000246:Adenosine Diphosphate Ribose; D010450:Endopeptidases