Neutral peptidase activities in matrix vesicles from bovine fetal alveolar bone and dog osteosarcoma

Hirschman, Albert O.; Deutsch, D.; Hirschman, M; Bab, Itai; Sela, J.; Mühlrád, András

doi:10.1007/bf02405125

Cited by 35 publications

(15 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The annexin family of proteins, which function as membrane channels and are thought to be involved in active uptake of Ca 2þ into the MVs, have previously been described as important in MV function (Kirsch, 2005). Enzyme activity such as that associated with type IV collagenase (MMP-2), aminopeptidase A and N (zinc metalloproteases) and Neprilysin (CD10), a type II integral membrane glycoprotein and zinc metalloprotease, have also been described (Hirschman et al, 1983;Dean et al, Fig. 5.…”

Section: Discussionmentioning

confidence: 99%

Analysis of the extracellular matrix vesicle proteome in mineralizing osteoblasts

Xiao

Camalier

Nagashima

et al. 2006

Journal Cellular Physiology

167

176

View full text Add to dashboard Cite

Many key processes central to bone formation and homeostasis require the involvement of osteoblasts, cells responsible for accumulation and mineralization of the extracellular matrix (ECM). During this complex and only partially understood process, osteoblasts generate and secrete matrix vesicles (MVs) into the ECM to initiate mineralization. Although they are considered an important component of mineralization process, MVs still remain a mystery. To better understand their function and biogenesis, a proteomic analysis of MVs has been conducted. MVs were harvested by two sample preparation approaches and mass spectrometry was utilized for protein identification. A total of 133 proteins were identified in common from the two MV preparations, among which were previously known proteins, such as annexins and peptidases, along with many novel proteins including a variety of enzymes, osteoblast-specific factors, ion channels, and signal transduction molecules, such as 14-3-3 family members and Rab-related proteins. To compare the proteome of MV with that of the ECM we conducted a large-scale proteomic analysis of collagenase digested mineralizing osteoblast matrix. This analysis resulted in the identification of 1,327 unique proteins. A comparison of the proteins identified from the two MV preparations with the ECM analysis revealed 83 unique, non-redundant proteins identified in all three samples. This investigation represents the first systematic proteomic analysis of MVs and provides insights into both the function and origin of these important mineralization-regulating vesicles.

show abstract

Section: Discussionmentioning

confidence: 99%

Analysis of the extracellular matrix vesicle proteome in mineralizing osteoblasts

Xiao

Camalier

Nagashima

et al. 2006

Journal Cellular Physiology

167

176

View full text Add to dashboard Cite

show abstract

“…In normal animals, the extracellular fluid bathing MVs contains homeostatically maintained levels of calcium and PO 4 sufficient to support continued nucleation of new HA crystals on preformed HA templates. Crystal perforation of the MV membranes would be augmented by phospholipases [31] and proteases [32] that are present within MVs. Propagation of mineral into the perivesicular matrix would be facilitated by metalloproteinases of MVs, which are capable of degrading mineralinhibiting proteoglycans [33].…”

Section: Mechanism Of Matrix Vesicle Calcificationmentioning

confidence: 99%

Matrix vesicles and calcification

2003

View full text Add to dashboard Cite

Matrix vesicles (MVs) are extracellular, 100 nM in diameter, membrane-invested particles selectively located at sites of initial calcification in cartilage, bone, and predentin. The first crystals of apatitic bone mineral are formed within MVs close to the inner surfaces of their investing membranes. Matrix vesicle biogenesis occurs by polarized budding and pinching-off of vesicles from specific regions of the outer plasma membranes of differentiating growth plate chondrocytes, osteoblasts, and odontoblasts. Polarized release of MVs into selected areas of developing matrix determines the nonrandom distribution of calcification. Initiation of the first mineral crystals, within MVs (phase 1), is augmented by the activity of MV phosphatases (eg, alkaline phosphatase, adenosine triphosphatase and pyrophosphatase) plus calcium-binding molecules (eg, annexin I and phosphatidyl serine), all of which are concentrated in or near the MV membrane. Phase 2 of biologic mineralization begins with crystal release through the MV membrane, exposing preformed hydroxyapatite crystals to the extracellular fluid. The extracellular fluid normally contains sufficient Ca2+ and PO4(3-) to support continuous crystal proliferation, with preformed crystals serving as nuclei (templates) for the formation of new crystals by a process of homologous nucleation. In diseases such as osteoarthritis, crystal deposition arthritis, and atherosclerosis, MVs initiate pathologic calcification, which, in turn, augments disease progression.

show abstract

“…Matrix vesicles have an active phospholipid metabolism which is regulated independently from that of the cell . Matrix vesicles also contain metalloproteinases capable of remodeling the extracellular matrix (Dean et al, 1992(Dean et al, , 1994Hirschman et al, 1983).…”

mentioning

confidence: 99%

Nongenomic regulation of protein kinase C isoforms by the vitamin D metabolites 1α,25-(OH)2D3 and 24R,25-(OH)2D3

et al. 1996

View full text Add to dashboard Cite

Prior studies have shown that vitamin D regulation of protein kinase C activity (PKC) in the cell layer of chondrocyte cultures is cell maturation-dependent. In the present study, we examined the membrane distribution of PKC and whether 1 alpha,25-(OH)2D3 and 24R,25-(OH)2D3 can directly regulate enzyme activity in isolated plasma membranes and extracellular matrix vesicles. Matrix vesicle PKC was activated by bryostatin-1 and inhibited by a PKC-specific pseudosubstrate inhibitor peptide. Depletion of membrane PKC activity using isoform-specific anti-PKC antibodies suggested that PKC alpha is the major isoform in cell layer lysates as well as in plasma membranes isolated from both cell types; PKC zeta is the predominant form in matrix vesicles. This was confirmed in Western blots of immunoprecipitates as well as in studies using control peptides to block binding of the isoform specific antibody to the enzyme and using a PKC zeta-specific pseudosubstrate inhibitor peptide. The presence of PKC zeta in matrix vesicles was further verified by immunoelectron microscopy. Enzyme activity in the matrix vesicle was insensitive to exogenous lipid, whereas that in the plasma membrane required lipid for full activity. 1,25-(OH)2D3 and 24,25-(OH)2D3 inhibited matrix vesicle PKC, but stimulated plasma membrane PKC when added directly to the isolated membrane fractions. PKC activity in the matrix vesicle was calcium-independent, whereas that in the plasma membrane required calcium. Moreover, the vitamin D-sensitive PKC in matrix vesicles was not dependent on calcium, whereas the vitamin D-sensitive enzyme in plasma membranes was calcium-dependent. It is concluded that PKC isoforms are differentially distributed between matrix vesicles and plasma membranes and that enzyme activity is regulated in a membrane-specific manner. This suggests the existence of a nongenomic mechanism whereby the effects of 1,25-(OH)2D3 and 24,25-(OH)2D3 may be mediated via PKC. Further, PKC zeta may be important in nongenomic, autocrine signal transduction at sites distal from the cell.

show abstract

Neutral peptidase activities in matrix vesicles from bovine fetal alveolar bone and dog osteosarcoma

Cited by 35 publications

References 17 publications

Analysis of the extracellular matrix vesicle proteome in mineralizing osteoblasts

Analysis of the extracellular matrix vesicle proteome in mineralizing osteoblasts

Matrix vesicles and calcification

Nongenomic regulation of protein kinase C isoforms by the vitamin D metabolites 1α,25-(OH)2D3 and 24R,25-(OH)2D3

Contact Info

Product

Resources

About