Binding of pyrin to stabilized microtubules in vitro.

Lysates were prepared from MEFV cDNA or mock-transfected cells and added to bovine brain microtubules stabilized with paclitaxel. Pyrin was detected with antipyrin antibody and horseradish peroxidase–linked anti–rabbit IgG. (A) Pyrin in lysates of Cos-7 cells transfected with MEFV cDNA was sedimented in the presence of microtubules (lane 1) but not when microtubules were absent (lanes 2). Mock-transfected cell lysates did not show any pyrin sedimentation with or without microtubules (lanes 3 and 4). Neither microtubules nor mock-transfected cell lysate contain pyrin (lane 5 and 7). Lysate from cells transfected with MEFV cDNA contained pyrin (lane 6). (B) Purified recombinant pyrin cosedimented with paclitaxel-stabilized microtubules (lane 1) with some pyrin remaining in the supernatant (lane 2). In the absence of microtubules, purified pyrin did not sediment (lane 3) but remained in the supernatant (lane 4). The microtubule preparation did not contain pyrin in the pellet (lane 5) or in the supernatant (lane 6).