hTIN2 isoforms interact similarly with known telomere-associated partners. HT1080 cells were infected with retroviruses expressing either FLAG-TIN2S, FLAG-TIN2L, no insert (pLXSN) or FLAG-TREM1 (negative control), as indicated in the bottom panel. After selection, the cells were lysed and immunoprecipitated using either anti-FLAG or non-specific IgG resin. Proteins were eluted from resin as described in Materials and Methods, and analyzed by western blotting using antibodies (WB) against tankyrase, TRF1, TRF2 or FLAG. 2.5% of the lysate (input) were also analyzed by western blotting.