Skip to main content
PMC home page
Protein Science : A Publication of the Protein Society logoLink to Protein Science : A Publication of the Protein Society
. 1994 May;3(5):822–830. doi: 10.1002/pro.5560030511

Conserved phosphorylation of serines in the Ser-X-Glu/Ser(P) sequences of the vitamin K-dependent matrix Gla protein from shark, lamb, rat, cow, and human.

P A Price 1, J S Rice 1, M K Williamson 1
PMCID: PMC2142713  PMID: 8061611

Abstract

The present studies demonstrate that matrix Gla protein (MGP), a 10-kDa vitamin K-dependent protein, is phosphorylated at 3 serine residues near its N-terminus. Phosphoserine was identified at residues 3, 6, and 9 of bovine, human, rat, and lamb MGP by N-terminal protein sequencing. All 3 modified serines are in tandemly repeated Ser-X-Glu sequences. Two of the serines phosphorylated in shark MGP, residues 2 and 5, also have glutamate residues in the n + 2 position in tandemly repeated Ser-X-Glu sequences, whereas the third, shark residue 3, would acquire an acidic phosphoserine in the n + 2 position upon phosphorylation of serine 5. The recognition motif found for MGP phosphorylation, Ser-X-Glu/Ser(P), has been seen previously in milk caseins, salivary proteins, and a number of regulatory peptides. A review of the literature has revealed an intriguing dichotomy in the extent of serine phosphorylation among secreted proteins that are phosphorylated at Ser-X-Glu/Ser(P) sequences. Those phosphoproteins secreted into milk or saliva are fully phosphorylated at each target serine, whereas phosphoproteins secreted into the extracellular environment of cells are partially phosphorylated at target serine residues, as we show here for MGP and others have shown for regulatory peptides and the insulin-like growth factor binding protein 1. We propose that the extent of serine phosphorylation regulates the activity of proteins secreted into the extracellular environment of cells, and that partial phosphorylation can therefore be explained by the need to ensure that the phosphoprotein be poised to gain or lose activity with regulated changes in phosphorylation status.(ABSTRACT TRUNCATED AT 250 WORDS)

Full Text

The Full Text of this article is available as a PDF (2.0 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bennett H. P., Brubaker P. L., Seger M. A., Solomon S. Human phosphoserine 31 corticotropin1-39. Isolation and characterization. J Biol Chem. 1983 Jul 10;258(13):8108–8112. [PubMed] [Google Scholar]
  2. Briehl M. M., Miesfeld R. L. Isolation and characterization of transcripts induced by androgen withdrawal and apoptotic cell death in the rat ventral prostate. Mol Endocrinol. 1991 Oct;5(10):1381–1388. doi: 10.1210/mend-5-10-1381. [DOI] [PubMed] [Google Scholar]
  3. Burch W. M., Correa J., Shively J. E., Powell D. R. The 25-kilodalton insulin-like growth factor (IGF)-binding protein inhibits both basal and IGF-I-mediated growth of chick embryo pelvic cartilage in vitro. J Clin Endocrinol Metab. 1990 Jan;70(1):173–180. doi: 10.1210/jcem-70-1-173. [DOI] [PubMed] [Google Scholar]
  4. Cancela L., Hsieh C. L., Francke U., Price P. A. Molecular structure, chromosome assignment, and promoter organization of the human matrix Gla protein gene. J Biol Chem. 1990 Sep 5;265(25):15040–15048. [PubMed] [Google Scholar]
  5. Desmond H., Varro A., Young J., Gregory H., Nemeth J., Dockray G. J. The constitution and properties of phosphorylated and unphosphorylated C-terminal fragments of progastrin from dog and ferret antrum. Regul Pept. 1989 May;25(2):223–233. doi: 10.1016/0167-0115(89)90264-4. [DOI] [PubMed] [Google Scholar]
  6. Dockray G. J., Varro A., Desmond H., Young J., Gregory H., Gregory R. A. Post-translational processing of the porcine gastrin precursor by phosphorylation of the COOH-terminal fragment. J Biol Chem. 1987 Jun 25;262(18):8643–8647. [PubMed] [Google Scholar]
  7. Eipper B. A., Mains R. E. Phosphorylation of pro-adrenocorticotropin/endorphin-derived peptides. J Biol Chem. 1982 May 10;257(9):4907–4915. [PubMed] [Google Scholar]
  8. Elgin R. G., Busby W. H., Jr, Clemmons D. R. An insulin-like growth factor (IGF) binding protein enhances the biologic response to IGF-I. Proc Natl Acad Sci U S A. 1987 May;84(10):3254–3258. doi: 10.1073/pnas.84.10.3254. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Fiat A. M., Jollès P. Caseins of various origins and biologically active casein peptides and oligosaccharides: structural and physiological aspects. Mol Cell Biochem. 1989 May 4;87(1):5–30. doi: 10.1007/BF00421079. [DOI] [PubMed] [Google Scholar]
  10. Fraser J. D., Price P. A. Lung, heart, and kidney express high levels of mRNA for the vitamin K-dependent matrix Gla protein. Implications for the possible functions of matrix Gla protein and for the tissue distribution of the gamma-carboxylase. J Biol Chem. 1988 Aug 15;263(23):11033–11036. [PubMed] [Google Scholar]
  11. George A., Sabsay B., Simonian P. A., Veis A. Characterization of a novel dentin matrix acidic phosphoprotein. Implications for induction of biomineralization. J Biol Chem. 1993 Jun 15;268(17):12624–12630. [PubMed] [Google Scholar]
  12. Hale J. E., Fraser J. D., Price P. A. The identification of matrix Gla protein in cartilage. J Biol Chem. 1988 Apr 25;263(12):5820–5824. [PubMed] [Google Scholar]
  13. Hale J. E., Williamson M. K., Price P. A. Carboxyl-terminal proteolytic processing of matrix Gla protein. J Biol Chem. 1991 Nov 5;266(31):21145–21149. [PubMed] [Google Scholar]
  14. Ikeda T., Yamaguchi A., Icho T., Tsuchida N., Yoshiki S. cDNA and deduced amino acid sequence of mouse matrix gla protein: one of five glutamic acid residues potentially modified to gla is not conserved in the mouse sequence. J Bone Miner Res. 1991 Sep;6(9):1013–1017. doi: 10.1002/jbmr.5650060916. [DOI] [PubMed] [Google Scholar]
  15. Isemura S., Saitoh E., Sanada K., Minakata K. Identification of full-sized forms of salivary (S-type) cystatins (cystatin SN, cystatin SA, cystatin S, and two phosphorylated forms of cystatin S) in human whole saliva and determination of phosphorylation sites of cystatin S. J Biochem. 1991 Oct;110(4):648–654. doi: 10.1093/oxfordjournals.jbchem.a123634. [DOI] [PubMed] [Google Scholar]
  16. Johansen J. S., Williamson M. K., Rice J. S., Price P. A. Identification of proteins secreted by human osteoblastic cells in culture. J Bone Miner Res. 1992 May;7(5):501–512. doi: 10.1002/jbmr.5650070506. [DOI] [PubMed] [Google Scholar]
  17. Jones J. I., Busby W. H., Jr, Wright G., Smith C. E., Kimack N. M., Clemmons D. R. Identification of the sites of phosphorylation in insulin-like growth factor binding protein-1. Regulation of its affinity by phosphorylation of serine 101. J Biol Chem. 1993 Jan 15;268(2):1125–1131. [PubMed] [Google Scholar]
  18. May L. T., Sehgal P. B. Phosphorylation of interleukin-6 at serine54: an early event in the secretory pathway in human fibroblasts. Biochem Biophys Res Commun. 1992 Jun 15;185(2):524–530. doi: 10.1016/0006-291x(92)91656-b. [DOI] [PubMed] [Google Scholar]
  19. Meggio F., Boulton A. P., Marchiori F., Borin G., Lennon D. P., Calderan A., Pinna L. A. Substrate-specificity determinants for a membrane-bound casein kinase of lactating mammary gland. A study with synthetic peptides. Eur J Biochem. 1988 Nov 1;177(2):281–284. doi: 10.1111/j.1432-1033.1988.tb14374.x. [DOI] [PubMed] [Google Scholar]
  20. Mercier J. C. Phosphorylation of caseins, present evidence for an amino acid triplet code posttranslationally recognized by specific kinases. Biochimie. 1981 Jan;63(1):1–17. doi: 10.1016/s0300-9084(81)80141-1. [DOI] [PubMed] [Google Scholar]
  21. Meyer H. E., Hoffmann-Posorske E., Korte H., Heilmeyer L. M., Jr Sequence analysis of phosphoserine-containing peptides. Modification for picomolar sensitivity. FEBS Lett. 1986 Aug 11;204(1):61–66. doi: 10.1016/0014-5793(86)81388-6. [DOI] [PubMed] [Google Scholar]
  22. Oldberg A., Franzén A., Heinegård D. Cloning and sequence analysis of rat bone sialoprotein (osteopontin) cDNA reveals an Arg-Gly-Asp cell-binding sequence. Proc Natl Acad Sci U S A. 1986 Dec;83(23):8819–8823. doi: 10.1073/pnas.83.23.8819. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Oppenheim F. G., Yang Y. C., Diamond R. D., Hyslop D., Offner G. D., Troxler R. F. The primary structure and functional characterization of the neutral histidine-rich polypeptide from human parotid secretion. J Biol Chem. 1986 Jan 25;261(3):1177–1182. [PubMed] [Google Scholar]
  24. Otawara Y., Price P. A. Developmental appearance of matrix GLA protein during calcification in the rat. J Biol Chem. 1986 Aug 15;261(23):10828–10832. [PubMed] [Google Scholar]
  25. Price P. A., Fraser J. D., Metz-Virca G. Molecular cloning of matrix Gla protein: implications for substrate recognition by the vitamin K-dependent gamma-carboxylase. Proc Natl Acad Sci U S A. 1987 Dec;84(23):8335–8339. doi: 10.1073/pnas.84.23.8335. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Price P. A., Urist M. R., Otawara Y. Matrix Gla protein, a new gamma-carboxyglutamic acid-containing protein which is associated with the organic matrix of bone. Biochem Biophys Res Commun. 1983 Dec 28;117(3):765–771. doi: 10.1016/0006-291x(83)91663-7. [DOI] [PubMed] [Google Scholar]
  27. Price P. A., Williamson M. K. Primary structure of bovine matrix Gla protein, a new vitamin K-dependent bone protein. J Biol Chem. 1985 Dec 5;260(28):14971–14975. [PubMed] [Google Scholar]
  28. Prince C. W., Oosawa T., Butler W. T., Tomana M., Bhown A. S., Bhown M., Schrohenloher R. E. Isolation, characterization, and biosynthesis of a phosphorylated glycoprotein from rat bone. J Biol Chem. 1987 Feb 25;262(6):2900–2907. [PubMed] [Google Scholar]
  29. Rannels S. R., Cancela M. L., Wolpert E. B., Price P. A. Matrix Gla protein mRNA expression in cultured type II pneumocytes. Am J Physiol. 1993 Sep;265(3 Pt 1):L270–L278. doi: 10.1152/ajplung.1993.265.3.L270. [DOI] [PubMed] [Google Scholar]
  30. Rice J. S., Williamson M. K., Price P. A. Isolation and sequence of the vitamin K-dependent matrix Gla protein from the calcified cartilage of the soupfin shark. J Bone Miner Res. 1994 Apr;9(4):567–576. doi: 10.1002/jbmr.5650090417. [DOI] [PubMed] [Google Scholar]
  31. Schlesinger D. H., Hay D. I. Complete covalent structure of statherin, a tyrosine-rich acidic peptide which inhibits calcium phosphate precipitation from human parotid saliva. J Biol Chem. 1977 Mar 10;252(5):1689–1695. [PubMed] [Google Scholar]
  32. Shanahan C. M., Weissberg P. L., Metcalfe J. C. Isolation of gene markers of differentiated and proliferating vascular smooth muscle cells. Circ Res. 1993 Jul;73(1):193–204. doi: 10.1161/01.res.73.1.193. [DOI] [PubMed] [Google Scholar]
  33. Varro A., Desmond H., Pauwels S., Gregory H., Young J., Dockray G. J. The human gastrin precursor. Characterization of phosphorylated forms and fragments. Biochem J. 1988 Dec 15;256(3):951–957. doi: 10.1042/bj2560951. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Watkinson A., Young J., Varro A., Dockray G. J. The isolation and chemical characterization of phosphorylated enkephalin-containing peptides from bovine adrenal medulla. J Biol Chem. 1989 Feb 25;264(6):3061–3065. [PubMed] [Google Scholar]
  35. Wong R. S., Bennick A. The primary structure of a salivary calcium-binding proline-rich phosphoprotein (protein C), a possible precursor of a related salivary protein A. J Biol Chem. 1980 Jun 25;255(12):5943–5948. [PubMed] [Google Scholar]
  36. Wrana J. L., Zhang Q., Sodek J. Full length cDNA sequence of porcine secreted phosphoprotein-I (SPP-I, osteopontin). Nucleic Acids Res. 1989 Dec 11;17(23):10119–10119. doi: 10.1093/nar/17.23.10119. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Protein Science : A Publication of the Protein Society are provided here courtesy of The Protein Society

RESOURCES