XB-IMG-83824
Xenbase Image ID: 83824
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Fig. 5. ST3 cleaves cell surface LR. A: Schematically diagram showing that ST3 cleavage sites are located between the transmembrane domain (TM)
and the laminin binding sequence (LB) of LR (Amano et al., 2005). ST3 cleaves LR between A115 and F116 (a), and P133 and I134 (b) and the two
cleavage sites by ST3 are indicated by two arrows. LR is either a homodimer of the 37-kd or a heterodimer with another protein (Landowski et al., 1995;
Menard et al., 1997; Buto et al., 1998). Only the 37-kd precursor protein (referred to here and in the text simply as LR) is shown here for simplicity.
B: Cos7 cells were transfected with a plasmid encoding C-terminal Flag-tagged LR and incubated with or without 2 or 5 g/ml of ST3Cw or ST3Cm
in the DMEM medium containing 2% FCS, 100 M ZnCl2, and 1 mM CaCl2. The cells and conditioned medium were isolated. Cells were lysed in
SDS-sample buffer and subjected to Western blotting with anti-Xenopus LR antibody (left). The conditioned medium was subjected to immunoprecipitation
with anti-Flag beads and the immunoprecipitate was analyzed on a Western blot with anti-Xenopus LR antibody (right). The arrow, and solid
and open circles indicate full-length LR and C-terminal degradation fragments, respectively. The full-length LR was likely due to cell lysis during protein
isolation, although some may also be due to secretion or shedding from cell surface (Karpatova et al., 1996). The star points to a non-specific band. Image published in: Amano T et al. (2005) Copyright © 2005. Image reproduced with permission of the Publisher, John Wiley & Sons. Larger Image Printer Friendly View |