Natural and induced mitochondrial phosphate carrier loss

Differential dependence of mitochondrial metabolism and dynamics and cell survival on the extent of depletion

Erin L. Seifert, Aniko Gál, Michelle G. Acoba, Qipei Li, Lauren Anderson-Pullinger, Tunde Golenár, Cynthia Moffat, Neal Sondheimer, Steven M Claypool, György Hajnóczky

Research output: Contribution to journalArticle

Abstract

The relevance of mitochondrial phosphate carrier (PiC), encoded by SLC25A3, in bioenergetics is well accepted. However, little is known about the mechanisms mediating the cellular impairments induced by pathological SLC25A3 variants. To this end, we investigated the pathogenicity of a novel compound heterozygous mutation in SLC25A3. First, each variant was modeled in yeast, revealing that substituting GSSAS for QIP within the fifth matrix loop is incompatible with survival on non-fermentable substrate, whereas the L200W variant is functionally neutral. Next, using skin fibroblasts from an individual expressing these variants and HeLa cells with varying degrees of PiC depletion, PiC loss of ∼60% was still compatible with uncompromised maximal oxidative phosphorylation (oxphos), whereas lower maximal oxphos was evident at ∼85% PiC depletion. Furthermore, intact mutant fibroblasts displayed suppressed mitochondrial bioenergetics consistent with a lower substrate availability rather than phosphate limitation. This was accompanied by slowed proliferation in glucose-replete medium; however, proliferation ceased when only mitochondrial substrate was provided. Both mutant fibroblasts and HeLa cells with 60% PiC loss showed a less interconnected mitochondrial network and a mitochondrial fusion defect that is not explained by altered abundance of OPA1 or MFN1/2 or relative amount of different OPA1 forms. Altogether these results indicate that PiC depletion may need to be profound (>85%) to substantially affect maximal oxphos and that pathogenesis associated with PiC depletion or loss of function may be independent of phosphate limitation when ATP requirements are not high.

Original languageEnglish (US)
Pages (from-to)26126-26137
Number of pages12
JournalJournal of Biological Chemistry
Volume291
Issue number50
DOIs
StatePublished - Dec 9 2016

Fingerprint

Phosphate Transport Proteins
Mitochondrial Dynamics
Oxidative Phosphorylation
Fibroblasts
Metabolism
Cell Survival
Cells
HeLa Cells
Energy Metabolism
Substrates
Phosphates
Yeast
Virulence
Skin
Fusion reactions
Adenosine Triphosphate
Yeasts
Availability
Glucose
Defects

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Natural and induced mitochondrial phosphate carrier loss : Differential dependence of mitochondrial metabolism and dynamics and cell survival on the extent of depletion. / Seifert, Erin L.; Gál, Aniko; Acoba, Michelle G.; Li, Qipei; Anderson-Pullinger, Lauren; Golenár, Tunde; Moffat, Cynthia; Sondheimer, Neal; Claypool, Steven M; Hajnóczky, György.

In: Journal of Biological Chemistry, Vol. 291, No. 50, 09.12.2016, p. 26126-26137.

Research output: Contribution to journalArticle

Seifert, Erin L. ; Gál, Aniko ; Acoba, Michelle G. ; Li, Qipei ; Anderson-Pullinger, Lauren ; Golenár, Tunde ; Moffat, Cynthia ; Sondheimer, Neal ; Claypool, Steven M ; Hajnóczky, György. / Natural and induced mitochondrial phosphate carrier loss : Differential dependence of mitochondrial metabolism and dynamics and cell survival on the extent of depletion. In: Journal of Biological Chemistry. 2016 ; Vol. 291, No. 50. pp. 26126-26137.
@article{236fb9266f1449b081c98810531681d1,
title = "Natural and induced mitochondrial phosphate carrier loss: Differential dependence of mitochondrial metabolism and dynamics and cell survival on the extent of depletion",
abstract = "The relevance of mitochondrial phosphate carrier (PiC), encoded by SLC25A3, in bioenergetics is well accepted. However, little is known about the mechanisms mediating the cellular impairments induced by pathological SLC25A3 variants. To this end, we investigated the pathogenicity of a novel compound heterozygous mutation in SLC25A3. First, each variant was modeled in yeast, revealing that substituting GSSAS for QIP within the fifth matrix loop is incompatible with survival on non-fermentable substrate, whereas the L200W variant is functionally neutral. Next, using skin fibroblasts from an individual expressing these variants and HeLa cells with varying degrees of PiC depletion, PiC loss of ∼60{\%} was still compatible with uncompromised maximal oxidative phosphorylation (oxphos), whereas lower maximal oxphos was evident at ∼85{\%} PiC depletion. Furthermore, intact mutant fibroblasts displayed suppressed mitochondrial bioenergetics consistent with a lower substrate availability rather than phosphate limitation. This was accompanied by slowed proliferation in glucose-replete medium; however, proliferation ceased when only mitochondrial substrate was provided. Both mutant fibroblasts and HeLa cells with 60{\%} PiC loss showed a less interconnected mitochondrial network and a mitochondrial fusion defect that is not explained by altered abundance of OPA1 or MFN1/2 or relative amount of different OPA1 forms. Altogether these results indicate that PiC depletion may need to be profound (>85{\%}) to substantially affect maximal oxphos and that pathogenesis associated with PiC depletion or loss of function may be independent of phosphate limitation when ATP requirements are not high.",
author = "Seifert, {Erin L.} and Aniko G{\'a}l and Acoba, {Michelle G.} and Qipei Li and Lauren Anderson-Pullinger and Tunde Golen{\'a}r and Cynthia Moffat and Neal Sondheimer and Claypool, {Steven M} and Gy{\"o}rgy Hajn{\'o}czky",
year = "2016",
month = "12",
day = "9",
doi = "10.1074/jbc.M116.744714",
language = "English (US)",
volume = "291",
pages = "26126--26137",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "50",

}

TY - JOUR

T1 - Natural and induced mitochondrial phosphate carrier loss

T2 - Differential dependence of mitochondrial metabolism and dynamics and cell survival on the extent of depletion

AU - Seifert, Erin L.

AU - Gál, Aniko

AU - Acoba, Michelle G.

AU - Li, Qipei

AU - Anderson-Pullinger, Lauren

AU - Golenár, Tunde

AU - Moffat, Cynthia

AU - Sondheimer, Neal

AU - Claypool, Steven M

AU - Hajnóczky, György

PY - 2016/12/9

Y1 - 2016/12/9

N2 - The relevance of mitochondrial phosphate carrier (PiC), encoded by SLC25A3, in bioenergetics is well accepted. However, little is known about the mechanisms mediating the cellular impairments induced by pathological SLC25A3 variants. To this end, we investigated the pathogenicity of a novel compound heterozygous mutation in SLC25A3. First, each variant was modeled in yeast, revealing that substituting GSSAS for QIP within the fifth matrix loop is incompatible with survival on non-fermentable substrate, whereas the L200W variant is functionally neutral. Next, using skin fibroblasts from an individual expressing these variants and HeLa cells with varying degrees of PiC depletion, PiC loss of ∼60% was still compatible with uncompromised maximal oxidative phosphorylation (oxphos), whereas lower maximal oxphos was evident at ∼85% PiC depletion. Furthermore, intact mutant fibroblasts displayed suppressed mitochondrial bioenergetics consistent with a lower substrate availability rather than phosphate limitation. This was accompanied by slowed proliferation in glucose-replete medium; however, proliferation ceased when only mitochondrial substrate was provided. Both mutant fibroblasts and HeLa cells with 60% PiC loss showed a less interconnected mitochondrial network and a mitochondrial fusion defect that is not explained by altered abundance of OPA1 or MFN1/2 or relative amount of different OPA1 forms. Altogether these results indicate that PiC depletion may need to be profound (>85%) to substantially affect maximal oxphos and that pathogenesis associated with PiC depletion or loss of function may be independent of phosphate limitation when ATP requirements are not high.

AB - The relevance of mitochondrial phosphate carrier (PiC), encoded by SLC25A3, in bioenergetics is well accepted. However, little is known about the mechanisms mediating the cellular impairments induced by pathological SLC25A3 variants. To this end, we investigated the pathogenicity of a novel compound heterozygous mutation in SLC25A3. First, each variant was modeled in yeast, revealing that substituting GSSAS for QIP within the fifth matrix loop is incompatible with survival on non-fermentable substrate, whereas the L200W variant is functionally neutral. Next, using skin fibroblasts from an individual expressing these variants and HeLa cells with varying degrees of PiC depletion, PiC loss of ∼60% was still compatible with uncompromised maximal oxidative phosphorylation (oxphos), whereas lower maximal oxphos was evident at ∼85% PiC depletion. Furthermore, intact mutant fibroblasts displayed suppressed mitochondrial bioenergetics consistent with a lower substrate availability rather than phosphate limitation. This was accompanied by slowed proliferation in glucose-replete medium; however, proliferation ceased when only mitochondrial substrate was provided. Both mutant fibroblasts and HeLa cells with 60% PiC loss showed a less interconnected mitochondrial network and a mitochondrial fusion defect that is not explained by altered abundance of OPA1 or MFN1/2 or relative amount of different OPA1 forms. Altogether these results indicate that PiC depletion may need to be profound (>85%) to substantially affect maximal oxphos and that pathogenesis associated with PiC depletion or loss of function may be independent of phosphate limitation when ATP requirements are not high.

UR - http://www.scopus.com/inward/record.url?scp=85002583964&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85002583964&partnerID=8YFLogxK

U2 - 10.1074/jbc.M116.744714

DO - 10.1074/jbc.M116.744714

M3 - Article

VL - 291

SP - 26126

EP - 26137

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 50

ER -