The zymogen granule protein 2 (GP2) binds to scavenger receptor expressed on endothelial cells I (SREC-I)

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• 作者：Markus A. Hö ; lzl^a ; Johannes Hofer^a ; Johannes J. Kovarik^a ; Dirk Roggenbuck^b ; Dirk Reinhold^c ; Alexander Goihl^c ; Miriam G&#xe4 ; rtner^a ; Peter Steinberger^a ; Gerhard J. Zlabinger^a ; ^{gerhard.zlabinger@meduniwien.ac.at}
• 关键词：SREC-I ; GP2 ; Dendritic cell ; THP ; Internalization ; acLDL
• 刊名：Cellular Immunology
• 出版年：2011
• 出版时间：2011
• 年：2011
• 卷：267
• 期：2
• 页码：88-93
• 全文大小：559 K

文摘

The pancreatic zymogen granule membrane protein (GP2) is expressed by pancreatic acinar cells and M cells of the ileum. GP2 is the closest related homologue of the urine resident Tamm–Horsfall protein (THP). Recently, it was shown that THP is a ligand of various scavenger receptors (SRs). Therefore, we were interested, if GP2 has similar properties.

cDNA of different SRs was stably transfected into a murine thymoma cell line. GP2 was recombinantly expressed, purified and biotinylated. Binding or uptake of GP2 by transfected cells or monocyte-derived dendritic cells (moDCs) was analyzed by flow-cytometry.

GP2 is a binding partner of the scavenger receptor expressed on endothelial cells I (SREC-I) but not of SR-AI and SR-BI. The dissociation constant (K_d) of GP2 binding to SREC-I is 41.3 nM. SREC transfected cells are able to internalize GP2. moDCs express SREC-I and also bind and internalize GP2. Inhibition of SREC-I on moDCs with anti-SREC-I antibodies does not result in a decreased GP2 binding.

Interaction of GP2 with SREC-I and uptake might have profound effects in antigen clearance and mediation of the immune response. In addition to SREC-I other presently unknown receptors for GP2 on DCs might be involved in this process.