Co-operative function and mutual stabilization of the half ATP-binding cassette transporters HAF-4 and HAF-9 in Caenorhabditis elegans

2013 ◽  
Vol 452 (3) ◽  
pp. 467-475 ◽  
Author(s):  
Takahiro Tanji ◽  
Kenji Nishikori ◽  
Hirohisa Shiraishi ◽  
Masatomo Maeda ◽  
Ayako Ohashi-Kobayashi
Keyword(s):  
Caenorhabditis Elegans ◽  
Antigen Processing ◽  
Fluorescent Protein ◽  
Peptide Transporter ◽  
Deletion Mutants ◽  
Atp Binding ◽  
Physical Interaction ◽  
Atp Binding Cassette Transporters ◽  
Green Fluorescent ◽  
Atp Binding Cassette

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.

scholarly journals Normal Formation of a Subset of Intestinal Granules in Caenorhabditis elegans Requires ATP-binding Cassette Transporters HAF-4 and HAF-9, Which Are Highly Homologous to Human Lysosomal Peptide Transporter TAP-Like

2009 ◽  
Vol 20 (12) ◽  
pp. 2979-2990 ◽  
Author(s):  
Hiromi Kawai ◽  
Takahiro Tanji ◽  
Hirohisa Shiraishi ◽  
Mitsuo Yamada ◽  
Ryoko Iijima ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Fluorescent Protein ◽  
Model Organism ◽  
Physiological Role ◽  
Peptide Transporter ◽  
Atp Binding ◽  
Loss Of Function ◽  
Specific Expression ◽  
Atp Binding Cassette

TAP-like (TAPL; ABCB9) is a half-type ATP-binding cassette (ABC) transporter that localizes in lysosome and putatively conveys peptides from cytosol to lysosome. However, the physiological role of this transporter remains to be elucidated. Comparison of genome databases reveals that TAPL is conserved in various species from a simple model organism, Caenorhabditis elegans, to mammals. C. elegans possesses homologous TAPL genes: haf-4 and haf-9. In this study, we examined the tissue-specific expression of these two genes and analyzed the phenotypes of the loss-of-function mutants for haf-4 and haf-9 to elucidate the in vivo function of these genes. Both HAF-4 and HAF-9 tagged with green fluorescent protein (GFP) were mainly localized on the membrane of nonacidic but lysosome-associated membrane protein homologue (LMP-1)-positive intestinal granules from larval to adult stage. The mutants for haf-4 and haf-9 exhibited granular defects in late larval and young adult intestinal cells, associated with decreased brood size, prolonged defecation cycle, and slow growth. The intestinal granular phenotype was rescued by the overexpression of the GFP-tagged wild-type protein, but not by the ATP-unbound form of HAF-4. These results demonstrate that two ABC transporters, HAF-4 and HAF-9, are related to intestinal granular formation and some other physiological aspects.

scholarly journals Fluorescent TAP as a Platform for Virus-Induced Degradation of the Antigenic Peptide Transporter

Cells ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1590 ◽  
Author(s):  
Magda Wąchalska ◽  
Małgorzata Graul ◽  
Patrique Praest ◽  
Rutger D. Luteijn ◽  
Aleksandra W. Babnis ◽  
...  
Keyword(s):  
Antigen Processing ◽  
Fluorescent Protein ◽  
Critical Role ◽  
Peptide Transporter ◽  
Virus Species ◽  
Protein Fusion ◽  
Fluorescent Properties ◽  
Bovine Herpesvirus 1 ◽  
Green Fluorescent

Transporter associated with antigen processing (TAP), a key player in the major histocompatibility complex class I-restricted antigen presentation, makes an attractive target for viruses that aim to escape the immune system. Mechanisms of TAP inhibition vary among virus species. Bovine herpesvirus 1 (BoHV-1) is unique in its ability to target TAP for proteasomal degradation following conformational arrest by the UL49.5 gene product. The exact mechanism of TAP removal still requires elucidation. For this purpose, a TAP-GFP (green fluorescent protein) fusion protein is instrumental, yet GFP-tagging may affect UL49.5-induced degradation. Therefore, we constructed a series of TAP-GFP variants using various linkers to obtain an optimal cellular fluorescent TAP platform. Mel JuSo (MJS) cells with CRISPR/Cas9 TAP1 or TAP2 knockouts were reconstituted with TAP-GFP constructs. Our results point towards a critical role of GFP localization on fluorescent properties of the fusion proteins and, in concert with the type of a linker, on the susceptibility to virally-induced inhibition and degradation. The fluorescent TAP platform was also used to re-evaluate TAP stability in the presence of other known viral TAP inhibitors, among which only UL49.5 was able to reduce TAP levels. Finally, we provide evidence that BoHV-1 UL49.5-induced TAP removal is p97-dependent, which indicates its degradation via endoplasmic reticulum-associated degradation (ERAD).

scholarly journals Stimulation of Cholesterol Excretion by the Liver X Receptor Agonist Requires ATP-binding Cassette Transporters G5 and G8

2003 ◽  
Vol 278 (18) ◽  
pp. 15565-15570 ◽  
Author(s):  
Liqing Yu ◽  
Jennifer York ◽  
Klaus von Bergmann ◽  
Dieter Lutjohann ◽  
Jonathan C. Cohen ◽  
...  
Keyword(s):  
Receptor Agonist ◽  
Liver X Receptor ◽  
Atp Binding ◽  
Atp Binding Cassette Transporters ◽  
Cholesterol Excretion ◽  
Liver X Receptor Agonist ◽  
Stimulation Of ◽  
Atp Binding Cassette

scholarly journals Dynamic Regulation of Caveolin-1 Trafficking in the Germ Line and Embryo of Caenorhabditis elegans

2006 ◽  
Vol 17 (7) ◽  
pp. 3085-3094 ◽  
Author(s):  
Ken Sato ◽  
Miyuki Sato ◽  
Anjon Audhya ◽  
Karen Oegema ◽  
Peter Schweinsberg ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Plasma Membrane ◽  
Caenorhabditis Elegans ◽  
Fluorescent Protein ◽  
Germ Line ◽  
Cortical Granule ◽  
Major Protein ◽  
Dynamic Regulation ◽  
Caveolin 1 ◽  
Green Fluorescent

Caveolin is the major protein component required for the formation of caveolae on the plasma membrane. Here we show that trafficking of Caenorhabditis elegans caveolin-1 (CAV-1) is dynamically regulated during development of the germ line and embryo. In oocytes a CAV-1-green fluorescent protein (GFP) fusion protein is found on the plasma membrane and in large vesicles (CAV-1 bodies). After ovulation and fertilization the CAV-1 bodies fuse with the plasma membrane in a manner reminiscent of cortical granule exocytosis as described in other species. Fusion of CAV-1 bodies with the plasma membrane appears to be regulated by the advancing cell cycle, and not fertilization per se, because fusion can proceed in spe-9 fertilization mutants but is blocked by RNA interference–mediated knockdown of an anaphase-promoting complex component (EMB-27). After exocytosis, most CAV-1-GFP is rapidly endocytosed and degraded within one cell cycle. CAV-1 bodies in oocytes appear to be produced by the Golgi apparatus in an ARF-1–dependent, clathrin-independent, mechanism. Conversely endocytosis and degradation of CAV-1-GFP in embryos requires clathrin, dynamin, and RAB-5. Our results demonstrate that the distribution of CAV-1 is highly dynamic during development and provides new insights into the sorting mechanisms that regulate CAV-1 localization.

scholarly journals Endocrine Disruptors Differentially Target ATP-Binding Cassette Transporters in the Blood-Testis Barrier and Affect Leydig Cell Testosterone Secretion In Vitro

2013 ◽  
Vol 136 (2) ◽  
pp. 382-391 ◽  
Author(s):  
Anita C. A. Dankers ◽  
Maarke J. E. Roelofs ◽  
Aldert H. Piersma ◽  
Fred C. G. J. Sweep ◽  
Frans G. M. Russel ◽  
...  
Keyword(s):  
Endocrine Disruptors ◽  
Leydig Cell ◽  
Atp Binding ◽  
Testosterone Secretion ◽  
Atp Binding Cassette Transporters ◽  
Blood Testis Barrier ◽  
Atp Binding Cassette
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