Evidence for multiple forms and modifications of human POT1.
Human POT1, a widely studied telomere protector protein is perceived to be expressed as a single 70kDa form. A survey of the literature as well as different commercially available antibodies against POT1 suggests occurrence of multiple forms of POT1. Knowledge about possible various forms of an important protein like POT1 is necessary for our understanding about its function. We have discovered that POT1 exists in at least three consistently occurring forms; 90, 70 and 45kDa. The unexpected molecular weights of POT1 seem to be associated with SUMO1 and ubiquitin conjugation; the latter occurring at a double lysine residue at 289-KK-290. We also present evidence that the relative abundance of the different POT1 forms can be altered by experimental modulation of POT1 nuclear localization. We thus present strong evidence that there are post-translational modifications of POT1 that can affect its molecular weight as well as intracellular localization and function.
Department of Immunology, Genetics and Pathology, Uppsala University, Dag Hammarskjölds Väg 20, Uppsala 75185, Sweden. Electronic address: umashankar.singh@igp.uu.se.
Umashankar
U
Singh
Varun
V
Maturi
Bengt
B
Westermark
D002467:Cell Nucleus / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D008239:Lysine / Q000378:metabolism; D008970:Molecular Weight; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D025842:SUMO-1 Protein / Q000378:metabolism*; D000089804:Shelterin Complex; D058207:Sumoylation; D034501:Telomere-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism
C440849:POT1 protein, human; D020033:Protein Isoforms; D025842:SUMO-1 Protein; D000089804:Shelterin Complex; D034501:Telomere-Binding Proteins; D025801:Ubiquitin; D008239:Lysine
POT1; Post-translational modifications; Unexpected molecular weights