Oxr1 and Ncoa7 regulate V-ATPase to achieve optimal pH for glycosylation within the Golgi apparatus and trans-Golgi network

Yoshimura, Shin Ichiro; Sobajima, Tomoaki; Kunii, Masataka; Harada, Akihiro

doi:https://doi.org/10.1073/pnas.2505975122

Oxr1 and Ncoa7 regulate V-ATPase to achieve optimal pH for glycosylation within the Golgi apparatus and trans-Golgi network

Yoshimura, Shin Ichiro; Sobajima, Tomoaki; Kunii, Masataka et al.

Proceedings of the National Academy of Sciences of the United States of America, 2025, 122(22), e2505975122

Number of Access:12（2025-11-15 01:26 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/102926

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Title	Oxr1 and Ncoa7 regulate V-ATPase to achieve optimal pH for glycosylation within the Golgi apparatus and trans-Golgi network
Creator	NRID 1000060584521 1000060584521 ORCID 0000-0003-3632-0674 0000-0003-3632-0674 researchmap permalink sw-510119 sw-510119 Scopus Author ID 35598338400 35598338400 CreatorName Yoshimura, Shin Ichiro
	CreatorName Sobajima, Tomoaki
	NRID 1000080614768 1000080614768 ORCID 0000-0001-7222-7456 0000-0001-7222-7456 researchmap permalink kunimasa kunimasa Scopus Author ID 23985234600 23985234600 CreatorName Kunii, Masataka
	NRID 1000040251441 1000040251441 researchmap permalink aharada aharada Scopus Author ID 7202253419 7202253419 CreatorName Harada, Akihiro
Subject	congenital disorders of glycosylation
	glycosylation
	Golgi apparatus/Trans-Golgi network
	Rab
	V-ATPase
Description	Yoshimura S.I., Sobajima T., Kunii M., et al. Oxr1 and Ncoa7 regulate V-ATPase to achieve optimal pH for glycosylation within the Golgi apparatus and trans-Golgi network. Proceedings of the National Academy of Sciences of the United States of America 122, e2505975122 (2025); https://doi.org/10.1073/pnas.2505975122.
Abstract	Maintenance of pH within membranous organelles is crucial for cellular processes such as posttranslational modifications, ligand–receptor interactions, and proteostasis. The precise mechanisms that determine the luminal pH of each organelle are not fully understood. This study investigated the mechanisms that regulate luminal pH to ensure optimal enzymatic activity. We identified Oxr1 and its paralog Ncoa7, which regulate the vacuolar-type proton pump ATPase (V-ATPase) at the Golgi apparatus and trans-Golgi network (TGN). Oxr1 and Ncoa7 were predominantly localized at the Golgi and TGN membranes, dependent on their binding to various GTP-bound Rab proteins. In vitro experiments using purified recombinant proteins indicated that Oxr1 and Ncoa7 directly bind to the catalytic subunit of V-ATPase, inhibiting its ATP hydrolytic activity via their TLDc domains. We observed significant acidification of the Golgi/TGN lumen in Oxr1- and Ncoa7-depleted cells. Lectin blot analysis demonstrated that depletion of Oxr1 and Ncoa7 led to a defect in protein glycosylation, a major enzymatic posttranslational modification in the Golgi and TGN. Furthermore, depletion of Oxr1 and Ncoa7, along with drug-induced inhibition of glycosylation, increased lysosomal pH and sensitivity to silicon dioxide-induced membrane damage. This apparent lysosomal dysfunction suggested that, in addition to the Golgi and TGN, Oxr1 and Ncoa7 also contribute to the integrity of other organelles. Our findings indicate that Oxr1 and Ncoa7 protect the Golgi and TGN lumen from excess acidification by inhibiting V-ATPase activity and providing an optimal environment for enzymatic activity in the Golgi and TGN.
Publisher	National Academy of Sciences
Source Title	Proceedings of the National Academy of Sciences of the United States of America
Volume (Issue)	122(22)
Page	e2505975122
Date of Issued	2025-05-30
Language	English
Handle URL	https://hdl.handle.net/11094/102926
PISSN	00278424
eISSN	10916490
Relation.isIdenticalTo	DOI (Publisher Version) https://doi.org/10.1073/pnas.2505975122
Access Rights	open access
CopyRight	This article is licensed under a Creative Commons Attribution 4.0 International License.
oaire:version	Version of Record
Category	学術雑誌論文 Journal Article

Resource Type	journal article
Local Type	Journal Article
DCMI Type	Text
DCTERMS.bibliographicCitation	Proceedings of the National Academy of Sciences of the United States of America. 2025, 122(22), p. e2505975122
DC.title	Oxr1 and Ncoa7 regulate V-ATPase to achieve optimal pH for glycosylation within the Golgi apparatus and trans-Golgi network
DC.creator	Yoshimura, Shin Ichiro
	Sobajima, Tomoaki
	Kunii, Masataka
	Harada, Akihiro
DC.publisher	National Academy of Sciences
DC.language' scheme='DCTERMS.RFC1766	English
DC.type' scheme='DCTERMS.DCMIType	Text
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2025-05-30
DC.identifier	https://doi.org/10.1073/pnas.2505975122
DC.subject	congenital disorders of glycosylation
	glycosylation
	Golgi apparatus/Trans-Golgi network
	Rab
	V-ATPase
DC.description	Yoshimura S.I., Sobajima T., Kunii M., et al. Oxr1 and Ncoa7 regulate V-ATPase to achieve optimal pH for glycosylation within the Golgi apparatus and trans-Golgi network. Proceedings of the National Academy of Sciences of the United States of America 122, e2505975122 (2025); https://doi.org/10.1073/pnas.2505975122.
DCTERMS.abstract	Maintenance of pH within membranous organelles is crucial for cellular processes such as posttranslational modifications, ligand–receptor interactions, and proteostasis. The precise mechanisms that determine the luminal pH of each organelle are not fully understood. This study investigated the mechanisms that regulate luminal pH to ensure optimal enzymatic activity. We identified Oxr1 and its paralog Ncoa7, which regulate the vacuolar-type proton pump ATPase (V-ATPase) at the Golgi apparatus and trans-Golgi network (TGN). Oxr1 and Ncoa7 were predominantly localized at the Golgi and TGN membranes, dependent on their binding to various GTP-bound Rab proteins. In vitro experiments using purified recombinant proteins indicated that Oxr1 and Ncoa7 directly bind to the catalytic subunit of V-ATPase, inhibiting its ATP hydrolytic activity via their TLDc domains. We observed significant acidification of the Golgi/TGN lumen in Oxr1- and Ncoa7-depleted cells. Lectin blot analysis demonstrated that depletion of Oxr1 and Ncoa7 led to a defect in protein glycosylation, a major enzymatic posttranslational modification in the Golgi and TGN. Furthermore, depletion of Oxr1 and Ncoa7, along with drug-induced inhibition of glycosylation, increased lysosomal pH and sensitivity to silicon dioxide-induced membrane damage. This apparent lysosomal dysfunction suggested that, in addition to the Golgi and TGN, Oxr1 and Ncoa7 also contribute to the integrity of other organelles. Our findings indicate that Oxr1 and Ncoa7 protect the Golgi and TGN lumen from excess acidification by inhibiting V-ATPase activity and providing an optimal environment for enzymatic activity in the Golgi and TGN.
DC.rights	This article is licensed under a Creative Commons Attribution 4.0 International License.
DC.format	102926
citation_title	Oxr1 and Ncoa7 regulate V-ATPase to achieve optimal pH for glycosylation within the Golgi apparatus and trans-Golgi network
citation_author	Yoshimura, Shin Ichiro
	Sobajima, Tomoaki
	Kunii, Masataka
	Harada, Akihiro
citation_publisher	National Academy of Sciences
citation_language	English
citation_date	2025-05-30
citation_journal_title	Proceedings of the National Academy of Sciences of the United States of America
citation_volume	122
citation_issue	22
citation_firstpage	e2505975122
citation_doi	https://doi.org/10.1073/pnas.2505975122
citation_public_url	https://hdl.handle.net/11094/102926

Oxr1 and Ncoa7 regulate V-ATPase to achieve optimal pH for glycosylation within the Golgi apparatus and trans-Golgi network

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