Co-operative function and mutual stabilization of the half ATP-binding cassette transporters HAF-4 and HAF-9 in Caenorhabditis elegans
| Autor: | Takahiro Tanji, Kenji Nishikori, Masatomo Maeda, Hirohisa Shiraishi, Ayako Ohashi-Kobayashi |
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| Rok vydání: | 2013 |
| Předmět: |
biology
Protein Stability Immunoprecipitation Mutant ATP-binding cassette transporter Cell Biology Transporter associated with antigen processing biology.organism_classification Biochemistry Cell biology Green fluorescent protein Animals Genetically Modified RNA interference Organelle Animals ATP-Binding Cassette Transporters Protein Multimerization Caenorhabditis elegans Caenorhabditis elegans Proteins Molecular Biology Gene Deletion |
| Zdroj: | Biochemical Journal. 452:467-475 |
| ISSN: | 1470-8728 0264-6021 |
| DOI: | 10.1042/bj20130115 |
| Popis: | Caenorhabditis elegans HAF-4 and HAF-9 are half ABC (ATP-binding-cassette) transporters that are highly homologous to the human lysosomal peptide transporter TAPL [TAP (transporter associated with antigen processing)-like; ABCB9]. We reported previously that both HAF-4 and HAF-9 localize to the membrane of a subset of intestinal organelles, and are required for the formation of these organelles and other physiological aspects. In the present paper, we report the genetic and physical interactions between HAF-4 and HAF-9. Overexpression of HAF-4 and HAF-9 did not rescue the intestinal organelle defect of the haf-9 and haf-4 deletion mutants respectively, indicating that they cannot substitute for each other. Double haf-4 and haf-9 mutants do not exhibit more severe phenotypes than the single mutants, suggesting their co-operative function. Immunoprecipitation experiments demonstrated their physical interaction. The results of the present study suggest that HAF-4 and HAF-9 form a heterodimer. Furthermore, Western blot analysis of the deletion mutants and RNAi (RNA interference) knockdown experiments in GFP (green fluorescent protein)-tagged HAF-4 or HAF-9 transgenic worms suggest that HAF-4–HAF-9 heterodimer formation is required for their stabilization. The findings provide a clue as to how ABC transporters adopt a stable functional form. |
| Databáze: | OpenAIRE |
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