Quantitative Analysis of TIP47-Receptor Cytoplasmic Domain Interactions
IMPLICATIONS FOR ENDOSOME-TO-TRANS GOLGI NETWORK TRAFFICKING*
- From the Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305-5307
Abstract
TIP47 (tail-interactingprotein of 47 kDa) binds to the cytoplasmic domains of the cation-independent and cation-dependent mannose 6-phosphate receptors and is required for their transport from late endosomes to the trans Golgi network in vitro andin vivo. We report here a quantitative analysis of the interaction of recombinant TIP47 with mannose 6-phosphate receptor cytoplasmic domains. Recombinant TIP47 binds more tightly to the cation-independent mannose 6-phosphate receptor (K D= 1 μm) than to the cation-dependent mannose 6-phosphate receptor (K D = 3 μm). In addition, TIP47 fails to interact with the cytoplasmic domains of the hormone-processing enzymes, furin, phosphorylated furin, and metallocarboxypeptidase D, as well as the cytoplasmic domain of TGN38, proteins that are also transported from endosomes to the trans Golgi network. Although these proteins failed to bind TIP47, furin and TGN38 were readily recognized by the clathrin adaptor, AP-2. These data suggest that TIP47 recognizes a very select set of cargo molecules. Moreover, our data suggest unexpectedly that furin, TGN38, and carboxypeptidase D may use a distinct vesicular carrier and perhaps a distinct route for transport between endosomes and the trans Golgi network.
Footnotes
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↵* This research was supported by a research grant from the National Institutes of Health (DK37336).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵‡ Supported by a postdoctoral fellowship from the Pharmaceutical Research and Manufacturers of America Foundation.
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↵§ Supported by a postdoctoral fellowship from the Leukemia Society.
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↵¶ Supported by a postdoctoral fellowship from the Human Frontier Science Program.
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↵‖ To whom correspondence should be addressed. Tel.: 650-723-6169; Fax: 650-723-6783; E-mail: pfeffer@cmgm.stanford.edu.
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Published, JBC Papers in Press, May 26, 2000, DOI 10.1074/jbc.M001138200
- Abbreviations:
- MPR
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mannose 6-phosphate receptor
- CI-MPR
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cation-independent MPR
- CD
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cation-dependent MPR
- CPD
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carboxypeptidase D
- TGN
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trans Golgi network
- GST
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glutathione S-transferase
- LDL
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low density lipoprotein
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- Received February 10, 2000.
- Revision received May 26, 2000.
- The American Society for Biochemistry and Molecular Biology, Inc.
