Sorting Signals Required for Trafficking of the Cysteine-Rich Acidic Repetitive Transmembrane Protein in Trypanosoma brucei
| Autor: | Yamei Jin, Chien-Hui Hung, Madhavi Muranjan, Xugang Qiao, Bin-Fay Chuang, Mary Gwo-Shu Lee, Pei-Tseng Lee |
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| Rok vydání: | 2006 |
| Předmět: |
Molecular Sequence Data
Trypanosoma brucei brucei Protozoan Proteins Protein Sorting Signals Trypanosoma brucei Endocytosis Microbiology Exocytosis Cell Line Animals Amino Acid Sequence Molecular Biology Peptide sequence biology C-terminus Endoplasmic reticulum Membrane Proteins Articles General Medicine biology.organism_classification Up-Regulation Transport protein Cell biology Protein Transport Biochemistry Flagella Mutation Signal Transduction |
| Zdroj: | Eukaryotic Cell. 5:1229-1242 |
| ISSN: | 1535-9786 1535-9778 5149-5163 |
| DOI: | 10.1128/ec.00064-06 |
| Popis: | In trypanosomatids, endocytosis and exocytosis are restricted to the flagellar pocket (FP). The c ysteine- r ich a cidic repetitive trans m embrane (CRAM) protein is located at the FP of Trypanosoma brucei and potentially functions as a receptor or an essential component for lipoprotein uptake. We characterized sorting determinants involved in efficient trafficking of CRAM to and from the FP of T. brucei . Previous studies indicated the presence of signals in the CRAM C terminus, specific for its localization to the FP and for efficient endocytosis (H. Yang, D. G. Russell, B. Zeng, M. Eiki, and M.G.-S. Lee, Mol. Cell. Biol. 20:5149-5163, 2000.) To delineate functional domains of putative sorting signals, we performed a mutagenesis series of the CRAM C terminus. Subcellular localization of CRAM mutants demonstrated that the amino acid sequence between −5 and −14 (referred to as a transport signal) is essential for exporting CRAM from the endoplasmic reticulum to the FP, and mutations of amino acids at −12 (V), −10 (V), or −5 (D) led to retention of CRAM in the endoplasmic reticulum. Comparison of the endocytosis efficiency of CRAM mutants demonstrated that the sequence from amino acid −5 to −23 (referred to as a putative endocytosis signal) is required for efficient endocytosis and overlaps with the transport signal. Apparently the CRAM-derived sorting signal can efficiently interact with the T. brucei μ1 adaptin, and mutations at amino acids essential for the function of the transport signal abolished the interaction of the signal with T. brucei μ1, strengthening the hypothesis of the involvement of the clathrin- and adaptor-dependent pathway in trafficking of CRAM via the FP. |
| Databáze: | OpenAIRE |
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