Fig. 1

Cathepsin Z is highly expressed in APCs but does not significantly contribute to phagolysosomal proteolysis. a Cathepsin Z mRNA levels in BV2 (C57BL/6 brain microglia cell line), DC2.4 (dendritic cell line), BMDC (bone marrow derived dendritic cells), pMØs (peritoneal macrophages), BMMØ (bone marrow derived macrophages), N2A (murine albino neuroblastoma cell line) and Cat Z^−/− BMDCs (n = 3). b-e The total proteolytic activity (rate of substrate-liberated fluorescence from the particle-bound fluorogenic substrate DQ-albumin) following phagocytosis of fluorometric experimental particles in WT and Cat Z^−/− (b-c) BMMØ (n = 9) and (d-e) BMDC (n = 5). b, d Representative real-time traces of phagosomal proteolysis. c, e Averaged rates of proteolysis (determined by calculation of the slope of the linear portion of the real-time trace [as described by y = mx + c, where y = relative fluorescence, m = slope, and x = time] were calculated between (c) 20 min and 60 min or (e) 20 min and 40 min after particle internalization. Data presented as mean+/− SEM; (c, e) no significant differences (unpaired Student’s t-test, p > 0.05) from the WT control were observed