FGF23 mutants causing familial tumoral calcinosis are differentially processed

Tobias Larsson, Siobhan I. Davis, Holly Garringer, Sean D. Mooney, Mohamad S. Draman, Michael J. Cullen, Kenneth White

Research output: Contribution to journalArticle

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Abstract

Familial tumoral calcinosis (TC, OMIM 211900) is a heritable disorder characterized by hyperphosphatemia, normal or elevated serum 1,25-dihydroxyvitamin D, and often severe ectopic calcifications. Two recessive mutations in Fibroblast growth factor-23 (FGF23), serine 71/glycine (S71G) and serine 129/phenylalanine (S129F), were identified as causing TC. Herein, we undertook comprehensive biochemical analyses of an extended TC family carrying the S71G FGF23 mutation, which revealed that heterozygous (serine/glycine, S/G) individuals had elevated serum FGF23 C-terminal fragments compared to wild type (serine/serine, S/S) family members (P<0.025). To understand the differential processing of FGF23 in TC patients, we transiently expressed S71G as well as S129F FGF23. FGF23 ELISA in tandem with Western analyses revealed increased proteolytic cleavage of mutant FGF23 and a limited secretion of intact protein. Furthermore, S71G and S129F FGF23 carrying mutations that disrupt the furin-like protease RXXR motif in FGF23 rescued the secretion of the intact protein, and both TC mutant proteins harboring the R176Q mutation revealed no altered sensitivity to trypsin compared to the native (R176Q)FGF23. Finally, S71G, but not S129F mutant FGF23, is rescued by temperature. In summary, FGF23 mutations causing TC lead to increased intracellular proteolysis of FGF23, most likely by furin-like proteases, and due to conformational changes of the mutant protein. The destabilizing nature of these mutations provides new insight into the pathophysiology of TC, and exemplifies the physiological importance of FGF23 in Pi and vitamin D metabolism.

Original languageEnglish
Pages (from-to)3883-3891
Number of pages9
JournalEndocrinology
Volume146
Issue number9
DOIs
StatePublished - Sep 2005

Fingerprint

Calcinosis
Serine
Glycine
Mutation
Furin
Mutant Proteins
fibroblast growth factor 23
Peptide Hydrolases
Hyperphosphatemia
Genetic Databases
Serum
Phenylalanine
Vitamin D
Trypsin
Proteolysis

Keywords

  • FGF23
  • Fibroblast Growth Factor 23
  • GALNT3
  • Hyperphosphatemia
  • Hypophosphatemia
  • Mutant
  • PHEX
  • SPC
  • Subtisilin-like pro-protein convertases
  • Tumoral calcinosis

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

FGF23 mutants causing familial tumoral calcinosis are differentially processed. / Larsson, Tobias; Davis, Siobhan I.; Garringer, Holly; Mooney, Sean D.; Draman, Mohamad S.; Cullen, Michael J.; White, Kenneth.

In: Endocrinology, Vol. 146, No. 9, 09.2005, p. 3883-3891.

Research output: Contribution to journalArticle

Larsson, T, Davis, SI, Garringer, H, Mooney, SD, Draman, MS, Cullen, MJ & White, K 2005, 'FGF23 mutants causing familial tumoral calcinosis are differentially processed', Endocrinology, vol. 146, no. 9, pp. 3883-3891. https://doi.org/10.1210/en.2005-0431
Larsson, Tobias ; Davis, Siobhan I. ; Garringer, Holly ; Mooney, Sean D. ; Draman, Mohamad S. ; Cullen, Michael J. ; White, Kenneth. / FGF23 mutants causing familial tumoral calcinosis are differentially processed. In: Endocrinology. 2005 ; Vol. 146, No. 9. pp. 3883-3891.
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abstract = "Familial tumoral calcinosis (TC, OMIM 211900) is a heritable disorder characterized by hyperphosphatemia, normal or elevated serum 1,25-dihydroxyvitamin D, and often severe ectopic calcifications. Two recessive mutations in Fibroblast growth factor-23 (FGF23), serine 71/glycine (S71G) and serine 129/phenylalanine (S129F), were identified as causing TC. Herein, we undertook comprehensive biochemical analyses of an extended TC family carrying the S71G FGF23 mutation, which revealed that heterozygous (serine/glycine, S/G) individuals had elevated serum FGF23 C-terminal fragments compared to wild type (serine/serine, S/S) family members (P<0.025). To understand the differential processing of FGF23 in TC patients, we transiently expressed S71G as well as S129F FGF23. FGF23 ELISA in tandem with Western analyses revealed increased proteolytic cleavage of mutant FGF23 and a limited secretion of intact protein. Furthermore, S71G and S129F FGF23 carrying mutations that disrupt the furin-like protease RXXR motif in FGF23 rescued the secretion of the intact protein, and both TC mutant proteins harboring the R176Q mutation revealed no altered sensitivity to trypsin compared to the native (R176Q)FGF23. Finally, S71G, but not S129F mutant FGF23, is rescued by temperature. In summary, FGF23 mutations causing TC lead to increased intracellular proteolysis of FGF23, most likely by furin-like proteases, and due to conformational changes of the mutant protein. The destabilizing nature of these mutations provides new insight into the pathophysiology of TC, and exemplifies the physiological importance of FGF23 in Pi and vitamin D metabolism.",
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AU - Larsson, Tobias

AU - Davis, Siobhan I.

AU - Garringer, Holly

AU - Mooney, Sean D.

AU - Draman, Mohamad S.

AU - Cullen, Michael J.

AU - White, Kenneth

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N2 - Familial tumoral calcinosis (TC, OMIM 211900) is a heritable disorder characterized by hyperphosphatemia, normal or elevated serum 1,25-dihydroxyvitamin D, and often severe ectopic calcifications. Two recessive mutations in Fibroblast growth factor-23 (FGF23), serine 71/glycine (S71G) and serine 129/phenylalanine (S129F), were identified as causing TC. Herein, we undertook comprehensive biochemical analyses of an extended TC family carrying the S71G FGF23 mutation, which revealed that heterozygous (serine/glycine, S/G) individuals had elevated serum FGF23 C-terminal fragments compared to wild type (serine/serine, S/S) family members (P<0.025). To understand the differential processing of FGF23 in TC patients, we transiently expressed S71G as well as S129F FGF23. FGF23 ELISA in tandem with Western analyses revealed increased proteolytic cleavage of mutant FGF23 and a limited secretion of intact protein. Furthermore, S71G and S129F FGF23 carrying mutations that disrupt the furin-like protease RXXR motif in FGF23 rescued the secretion of the intact protein, and both TC mutant proteins harboring the R176Q mutation revealed no altered sensitivity to trypsin compared to the native (R176Q)FGF23. Finally, S71G, but not S129F mutant FGF23, is rescued by temperature. In summary, FGF23 mutations causing TC lead to increased intracellular proteolysis of FGF23, most likely by furin-like proteases, and due to conformational changes of the mutant protein. The destabilizing nature of these mutations provides new insight into the pathophysiology of TC, and exemplifies the physiological importance of FGF23 in Pi and vitamin D metabolism.

AB - Familial tumoral calcinosis (TC, OMIM 211900) is a heritable disorder characterized by hyperphosphatemia, normal or elevated serum 1,25-dihydroxyvitamin D, and often severe ectopic calcifications. Two recessive mutations in Fibroblast growth factor-23 (FGF23), serine 71/glycine (S71G) and serine 129/phenylalanine (S129F), were identified as causing TC. Herein, we undertook comprehensive biochemical analyses of an extended TC family carrying the S71G FGF23 mutation, which revealed that heterozygous (serine/glycine, S/G) individuals had elevated serum FGF23 C-terminal fragments compared to wild type (serine/serine, S/S) family members (P<0.025). To understand the differential processing of FGF23 in TC patients, we transiently expressed S71G as well as S129F FGF23. FGF23 ELISA in tandem with Western analyses revealed increased proteolytic cleavage of mutant FGF23 and a limited secretion of intact protein. Furthermore, S71G and S129F FGF23 carrying mutations that disrupt the furin-like protease RXXR motif in FGF23 rescued the secretion of the intact protein, and both TC mutant proteins harboring the R176Q mutation revealed no altered sensitivity to trypsin compared to the native (R176Q)FGF23. Finally, S71G, but not S129F mutant FGF23, is rescued by temperature. In summary, FGF23 mutations causing TC lead to increased intracellular proteolysis of FGF23, most likely by furin-like proteases, and due to conformational changes of the mutant protein. The destabilizing nature of these mutations provides new insight into the pathophysiology of TC, and exemplifies the physiological importance of FGF23 in Pi and vitamin D metabolism.

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KW - PHEX

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KW - Subtisilin-like pro-protein convertases

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