| First Author | Wood TR | Year | 2013 |
| Journal | J Leukoc Biol | Volume | 94 |
| Issue | 1 | Pages | 109-22 |
| PubMed ID | 23670290 | Mgi Jnum | J:201847 |
| Mgi Id | MGI:5515861 | Doi | 10.1189/jlb.1212634 |
| Citation | Wood TR, et al. (2013) PKC-epsilon pseudosubstrate and catalytic activity are necessary for membrane delivery during IgG-mediated phagocytosis. J Leukoc Biol 94(1):109-22 |
| abstractText | In RAW 264.7 cells, PKC-epsilon regulates FcgammaR-mediated phagocytosis. BMDM behave similarly; PKC-epsilon concentrates at phagosomes and internalization are reduced in PKC-epsilon(-)/(-) cells. Two questions were asked: what is the role of PKC-epsilon? and what domains are necessary for PKC-epsilon concentration? Function was studied using BMDM and frustrated phagocytosis. On IgG surfaces, PKC-epsilon(-)/(-) macrophages spread less than WT. Patch-clamping revealed that the spreading defect is a result of the failure of PKC-epsilon(-)/(-) macrophages to add membrane. The defect is specific for FcgammaR ligation and can be reversed by expression of full-length (but not the isolated RD) PKC-epsilon in PKC-epsilon(-)/(-) BMDM. Thus, PKC-epsilon function in phagocytosis requires translocation to phagosomes and the catalytic domain. The expression of chimeric PKC molecules in RAW cells identified the epsilonPS as necessary for PKC-epsilon targeting. When placed into (nonlocalizing) PKC-delta, epsilonPS was sufficient for concentration, albeit to a lesser degree than intact PKC-epsilon. In contrast, translocation of delta(epsilonPSC1B) resembled that of WT PKC-epsilon. Thus, epsilonPS and epsilonC1B cooperate for optimal phagosome targeting. Finally, cells expressing epsilonK437W were significantly less phagocytic than their PKC-epsilon-expressing counterparts, blocked at the pseudopod-extension phase. In summary, we have shown that epsilonPS and epsilonC1B are necessary and sufficient for targeting PKC-epsilon to phagosomes, where its catalytic activity is required for membrane delivery and pseudopod extension. |
