Association of LMP1 mutants with lipid rafts and cytoskeleton.
(A) Triton X-100 (0.2%) lysates from BJAB cells or
cells stably expressing wild-type LMP1, PQAA, or ID mutant were
subjected to sucrose gradient centrifugation, and aliquots of the peak
lipid raft (r), soluble (s), and pellet (p) fractions were probed with
anti-LMP1, TRAF3, TRAF2, or TRAF1 antibodies. (B)
Gradient fractions from wild-type, 1–231, or 1–231 PQAA
LMP1-expressing cells were immunoprecipitated with M2 gel and probed
with Flag antibody. Arrows indicate wild-type or mutant LMP1. Ig heavy
chain is indicated by asterisk. (C) Lysates from LMP2A
null mutant, D1LMP1-expressing ES5 cells were subjected to sucrose
gradient centrifugation, and the fractions were probed with LMP1
antibody.