This is a Pannexin-1 (Panx1) mimetic blocking peptide. Pannexin-1 is a recently identified membrane protein that can form gap junction-like connections allowing intercellular passage of dyes when overexpressed in two adjacent oocytes or mammalian epithelial cell lines. Blockade of pannexin-1 in macrophage endogenously expressing the ATP-gated P2X7 receptor (P2X7R) blocks the initial dye uptake, but not the ionic current, and also blocks processing and release of interleukin-1? (IL-1?) in response to P2X7R activation.