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Structure of the novel C-terminal domain of vacuolar protein sorting 30/autophagy-related protein 6 and its specific role in autophagy.

Noda NN, Kobayashi T, Adachi W, Fujioka Y, Ohsumi Y, Inagaki F - J. Biol. Chem. (2012)

Bottom Line: Thus, the domain is named the β-α repeated, autophagy-specific (BARA) domain.On the other hand, the N-terminal region of Vps30 was shown to be specifically required for vacuolar protein sorting.These structural and functional investigations of Vps30 domains, which are also conserved in the mammalian ortholog, Beclin 1, will form the basis for studying the molecular functions of this protein family in various biological processes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microbial Chemistry, Tokyo, Tokyo 141-0021, Japan. nn@bikaken.or.jp

ABSTRACT
Vacuolar protein sorting 30 (Vps30)/autophagy-related protein 6 (Atg6) is a common component of two distinct phosphatidylinositol 3-kinase complexes. In complex I, Atg14 links Vps30 to Vps34 lipid kinase and exerts its specific role in autophagy, whereas in complex II, Vps38 links Vps30 to Vps34 and plays a crucial role in vacuolar protein sorting. However, the molecular role of Vps30 in each pathway remains unclear. Here, we report the crystal structure of the carboxyl-terminal domain of Vps30. The structure is a novel globular fold comprised of three β-sheet-α-helix repeats. Truncation analyses showed that the domain is dispensable for the construction of both complexes, but is specifically required for autophagy through the targeting of complex I to the pre-autophagosomal structure. Thus, the domain is named the β-α repeated, autophagy-specific (BARA) domain. On the other hand, the N-terminal region of Vps30 was shown to be specifically required for vacuolar protein sorting. These structural and functional investigations of Vps30 domains, which are also conserved in the mammalian ortholog, Beclin 1, will form the basis for studying the molecular functions of this protein family in various biological processes.

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Summary of the functions of Vps30 domains revealed in this study.
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Figure 8: Summary of the functions of Vps30 domains revealed in this study.

Mentions: Based on this domain definition, we established the functions of NTD, CCD, and BARA of Vps30. They are summarized in Fig. 8. Vps30BARA is dispensable for the interaction with both Atg14 and Vps38 and for CPY sorting, but is crucial for autophagy through the targeting of the PI 3-kinase complex I to the PAS. On the other hand, Vps30NTD is necessary for the interaction with Vps38 but not with Atg14, and is crucial for CPY sorting but not for autophagy. Vps30CCD is crucial for the interaction with Atg14 and presumably with Vps38 too, and thus appears to be essential for both autophagy and CPY sorting. During truncation analysis, we succeeded in obtaining Vps30 mutants whose activity is restricted to either autophagy (Vps30CCD+BARA) or CPY sorting (Vps30ΔBARA). These Vps30 mutants would be helpful for studying the Vps30 functions in autophagy and CPY sorting separately. Furthermore, such truncation analyses would also be beneficial to study mammalian Beclin 1, which interacts with various factors and appears to play crucial roles in various membrane trafficking events besides autophagy (9, 11).


Structure of the novel C-terminal domain of vacuolar protein sorting 30/autophagy-related protein 6 and its specific role in autophagy.

Noda NN, Kobayashi T, Adachi W, Fujioka Y, Ohsumi Y, Inagaki F - J. Biol. Chem. (2012)

Summary of the functions of Vps30 domains revealed in this study.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3351336&req=5

Figure 8: Summary of the functions of Vps30 domains revealed in this study.
Mentions: Based on this domain definition, we established the functions of NTD, CCD, and BARA of Vps30. They are summarized in Fig. 8. Vps30BARA is dispensable for the interaction with both Atg14 and Vps38 and for CPY sorting, but is crucial for autophagy through the targeting of the PI 3-kinase complex I to the PAS. On the other hand, Vps30NTD is necessary for the interaction with Vps38 but not with Atg14, and is crucial for CPY sorting but not for autophagy. Vps30CCD is crucial for the interaction with Atg14 and presumably with Vps38 too, and thus appears to be essential for both autophagy and CPY sorting. During truncation analysis, we succeeded in obtaining Vps30 mutants whose activity is restricted to either autophagy (Vps30CCD+BARA) or CPY sorting (Vps30ΔBARA). These Vps30 mutants would be helpful for studying the Vps30 functions in autophagy and CPY sorting separately. Furthermore, such truncation analyses would also be beneficial to study mammalian Beclin 1, which interacts with various factors and appears to play crucial roles in various membrane trafficking events besides autophagy (9, 11).

Bottom Line: Thus, the domain is named the β-α repeated, autophagy-specific (BARA) domain.On the other hand, the N-terminal region of Vps30 was shown to be specifically required for vacuolar protein sorting.These structural and functional investigations of Vps30 domains, which are also conserved in the mammalian ortholog, Beclin 1, will form the basis for studying the molecular functions of this protein family in various biological processes.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microbial Chemistry, Tokyo, Tokyo 141-0021, Japan. nn@bikaken.or.jp

ABSTRACT
Vacuolar protein sorting 30 (Vps30)/autophagy-related protein 6 (Atg6) is a common component of two distinct phosphatidylinositol 3-kinase complexes. In complex I, Atg14 links Vps30 to Vps34 lipid kinase and exerts its specific role in autophagy, whereas in complex II, Vps38 links Vps30 to Vps34 and plays a crucial role in vacuolar protein sorting. However, the molecular role of Vps30 in each pathway remains unclear. Here, we report the crystal structure of the carboxyl-terminal domain of Vps30. The structure is a novel globular fold comprised of three β-sheet-α-helix repeats. Truncation analyses showed that the domain is dispensable for the construction of both complexes, but is specifically required for autophagy through the targeting of complex I to the pre-autophagosomal structure. Thus, the domain is named the β-α repeated, autophagy-specific (BARA) domain. On the other hand, the N-terminal region of Vps30 was shown to be specifically required for vacuolar protein sorting. These structural and functional investigations of Vps30 domains, which are also conserved in the mammalian ortholog, Beclin 1, will form the basis for studying the molecular functions of this protein family in various biological processes.

Show MeSH