Acidic Matrix Protein, Pif, Is a Key Macromolecule for Nacre Formation

• Published in: Science (American Association for the Advancement of Science) Vol. 325; no. 5946; pp. 1388 - 1390
• Main Authors: Suzuki, Michio, Saruwatari, Kazuko, Kogure, Toshihiro, Yamamoto, Yuya, Nishimura, Tatsuya, Kato, Takashi, Nagasawa, Hiromichi
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 11.09.2009; The American Association for the Advancement of Science
• Subjects: Amino Acid Sequence; Animals; Aragonite; Biochemistry. Physiology. Immunology; Biological and medical sciences; Calcification, Physiologic; Calcium carbonate; Calcium Carbonate - chemistry; Calcium Carbonate - metabolism; Calcium carbonates; Chemical compounds; Chitin; Complementary DNA; Crystallization; Crystals; DNA, Complementary; Epithelial Cells - metabolism; Fundamental and applied biological sciences. Psychology; Glass; Hydrogen-Ion Concentration; Immunohistochemistry; Invertebrates; Molecular Sequence Data; Molecules; Mollusca; Mollusks; nacre; Nanoparticles; oysters; Pearls; Physiology. Development; Pinctada - chemistry; Pinctada - metabolism; Pinctada fucata; Protein Precursors - genetics; Protein Precursors - metabolism; Protein Processing, Post-Translational; Proteins; Proteins - chemistry; Proteins - genetics; Proteins - metabolism; RNA Interference; shell (molluscs); Crystallization; Biomineralization; Biosynthesis; Protein; Regulation(control); Complementary DNA; Bivalvia; Mineralization; Macromolecule; Calcium carbonate; Mother of pearl; Invertebrata; Mollusca
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.1173793

The mollusk shell is a hard tissue consisting of calcium carbonate crystals and an organic matrix. The nacre of the shell is characterized by a stacked compartment structure with a uniformly oriented c axis of aragonite crystals in each compartment. Using a calcium carbonate-binding assay, we identified an acidic matrix protein, Pif, in the pearl oyster Pinctada fucata that specifically binds to aragonite crystals. The Pif complementary DNA (cDNA) encoded a precursor protein, which was posttranslationally cleaved to produce Pif 97 and Pif 80. The results from immunolocalization, a knockdown experiment that used RNA interference, and in vitro calcium carbonate crystallization studies strongly indicate that Pif regulates nacre formation.