Phosphorylation of serine residues is fundamental for the calcium-binding ability of Orchestin, a soluble matrix protein from crustacean calcium storage structures.
Orchestia cavimana is a terrestrial crustacean, which cyclically stores calcium in diverticula of the midgut, in the form of calcified amorphous concretions. These concretions are associated with a proteinaceous matrix, the main constituent of the soluble matrix is Orchestin, an acidic calcium-binding protein [Testenière et al., Biochem. J. 361 (2002) 327-335]. In the present paper, we clearly demonstrate that Orchestin is phosphorylated on serine and tyrosine residues, but that calcium binding only occurs via the phosphoserine residues. To our knowledge, this is the first example of an invertebrate mineralization for which a post-translational modification is clearly related to an important function of a calcifying protein.
Hecker
Arnaud
A
UMR CNRS 5548, Développement-Communication chimique, Université de Bourgogne, 6 Bd Gabriel, F-21000 Dijon, France.
Testenière
Olivier
O
Marin
Frédéric
F
Luquet
Gilles
G
D000595:Amino Acid Sequence; D000818:Animals; D002113:Calcification, Physiologic / Q000502:physiology; D002118:Calcium / Q000737:chemistry* / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D003445:Crustacea; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011485:Protein Binding / Q000502:physiology; D011499:Protein Processing, Post-Translational; D012694:Serine / Q000737:chemistry; D013329:Structure-Activity Relationship; D014443:Tyrosine / Q000737:chemistry
D002135:Calcium-Binding Proteins; C446561:orchestin protein, Orchestia cavimana; D014443:Tyrosine; D012694:Serine; D002118:Calcium