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. 2012 Mar 9;7(3):e33142. doi: 10.1371/journal.pone.0033142

Figure 6. CD44-augmentation of phagocytosis is associated with phosphorylation of paxillin and Rac2 activation.

Figure 6

A) Monocyte-derived macrophages were incubated with CD44 mAb at 37°C for different time points up to 60 min prior to lysis in RIPA buffer. Immunoblot analysis of tyrosine phosphorylation of paxillin revealed a time-dependent increase in phosphorylation following CD44 antibody binding. Image shows representative autoradiograph of a single experiment from 3 that were performed. Densitometric analysis of the phosphopaxillin using ImageJ (http://rsbweb.nih.gov/ij/) confirms increased phosphorylation of paxillin following CD44 treatment. For control phosphopaxillin levels at 0, 15, 30, 45 and 60 min was 7.7, 9.9, 9.3 and 8.2 respectively. In contrast, phosphopaxillin levels following CD44 cross-linking were 3.7, 8.8, 13.7, 12.4 and 15.6 at 0, 15, 30, 45 and 60 min respectively. Molecular weight standards shown in KDa. B) Monocyte-derived macrophages were incubated with either control IgG1 or CD44 mAb at 37°C for different times up to 20 min prior to lysis in RIPA buffer as indicated. Pull down assays using PAK CRIB agarose beads revealed a robust increase in GTP-bound Rac2 in the presence but not absence of CD44 antibody binding. A representative autoradiograph from a single experiment (from 5 that were performed) is shown.