Zymosan phagocytosis in RAW264.7 macrophages expressing various forms of HA-tagged Dectin-1. RAW264.7 macrophages expressing Dectin-1 lacking the cytoplasmic tail (Trunc) or mutations in the membrane proximal tyrosine of the cytoplasmic ITAM-like motif (Y1 and Y1/Y2) were unable to internalize bound zymosan. No effect on phagocytosis was observed with mutations in the membrane distal tyrosine (Y2). Cells expressing full-length Dectin-1 were pretreated with cytochalasin D to block internalization, as a control. Zymosan phagocytosis in these cells was synchronized and allowed to occur for 60 minutes. Dectin-1 was visualized by staining for the HA tag (red), using an APO oil immersion lens at 60× magnification, 1.4 NA.