Fig. 1 | Nature Communications

Fig. 1

From: Oligomerization-primed coiled-coil domain interaction with Ubc13 confers processivity to TRAF6 ubiquitin ligase activity

Fig. 1

Only long free polyubiquitin chains potently activate TAK1 kinase. a Purification scheme of polyubiquitin (polyUb) chains. b Purification scheme of endogenous TAK1 kinase complex. c Potent TAK1 activation by high molecular size polyUb chains. Partially purified TAK1 complex as in b was incubated with different sizes of polyUb chains after their fractionation as in a in the presence of ATP for 60 min at 30 °C. Aliquots of the reaction products were analyzed by immunoblotting with the indicated antibodies. The size distribution of the polyUb chains is shown in the bottom panel. d The relative amounts of polyUb chains used in c were determined by immunoblotting with anti-Ub antibody after their complete disassembly by DUB vOTU. e The chain length rather than the concentration of polyUb chains contributes more to TAK1 stimulatory activity. As in c, TAK1 was incubated with increasing amounts of long polyUb chains (Fraction A6) or short polyUb chains (Fraction B7) to determine its dose response to polyUb chains. S.E. short exposure, L.E. long exposure, M.W. molecular weight (KDa)

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