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Fig. 6. In vitro binding assays of hGAR17 and hGAR22 proteins. hGAR17 (A) or hGAR22
(B) proteins labeled with 35[S]-methionine were incubated with
preassembled MFs (+MF) or MTs (+MT), the reaction mixtures centrifuged at high
speed and the resulting supernatant (S) and pellet (P) fractions run on an
SDS-PAGE gel. The gels were dried and the radioactively labeled proteins
visualized by autoradiography. The presence of a protein in a pellet fraction
indicates binding to the corresponding filaments. Reactions without filaments
(MF, MT) were run to control for non-specific protein
aggregation. BSA was used as a non-binding negative control; in this case the
protein was visualized by Coomassie staining. The results of the assays are
indicated to the right of the gels (+, binding; , absence of binding).
Since hCt22 sedimented in the absence of MFs, its sedimentation with MFs
(+/) is most probably due to non-specific aggregation rather than
specific filament binding.