Matrix vesicles are located within the extracellular space, or matrix. Using electron microscopy, they were discovered independently in 1967 by H. Clarke Anderson and Ermanno Bonucci. These cell-derived vesicles are specialized to initiate biomineralisation of the matrix in a variety of tissues, including bone, cartilage and dentin. During normal calcification, a major influx of calcium and phosphate ions into the cells accompanies cellular apoptosis (genetically determined self-destruction) and matrix vesicle formation. Calcium-loading also leads to formation of phosphatidylserine:calcium:phosphate complexes in the plasma membrane mediated in part by a protein called annexins. Matrix vesicles bud from the plasma membrane at sites of interaction with the extracellular matrix. Thus, matrix vesicles convey to the extracellular matrix calcium, phosphate, lipids and the annexins which act to nucleate mineral formation. These processes are precisely coordinated to bring about, at the proper place and time, mineralization of the tissue's matrix unless the Golgi are non-existent.
Matrix vesicles are located within the extracellular space, or matrix. Using electron microscopy, they were discovered independently in 1967 by H. Clarke Anderson and Ermanno Bonucci. These cell-derived vesicles are specialized to initiate biomineralisation of the matrix in a variety of tissues, including bone, cartilage and dentin During normal calcification, a major influx of calcium and phosphate ions into the cells accompanies cellular apoptosis (genetically determined self-destruction) and matrix vesicle formation. Calcium-loading also leads to formation of phosphatidylserine:calcium:phosphate complexes in the plasma membrane mediated in part by a protein called annexins. Matrix vesicles bud from the plasma membrane at sites of interaction with the extracellular matrix. Thus, matrix vesicles convey to the extracellular matrix calcium, phosphate, lipids and the annexins which act to nucleate mineral formation. These processes are precisely coordinated to bring about, at the proper place and time, mineralization of the tissue's matrix unless the Golgi are non-existent.