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Hemopexin Family
The hemopexin family is a family of evolutionarily related proteins. Hemopexin-like repeats occur in vitronectin and some matrix metalloproteinases family (matrixins). The HX repeats of some matrixins bind tissue inhibitor of metallopeptidases ( TIMPs). Hemopexin () is a serum glycoprotein that binds haem and transports it to the liver for breakdown and iron recovery, after which the free hemopexin returns to the circulation. Hemopexin prevents haem-mediated oxidative stress. Structurally hemopexin consists of two similar halves of approximately two hundred amino acid residues connected by a histidine-rich hinge region. Each half is itself formed by the repetition of a basic unit of some 35 to 45 residues. Hemopexin-like domains have been found in two other types of proteins, vitronectin, a cell adhesion and spreading factor found in plasma and tissues, and matrixins MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, MMP-11, MMP-12, MMP-14, MMP-15 and MMP-16, members of the matrix metalloproteina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Family
A protein family is a group of evolutionarily related proteins. In many cases, a protein family has a corresponding gene family, in which each gene encodes a corresponding protein with a 1:1 relationship. The term "protein family" should not be confused with Family (biology), family as it is used in taxonomy. Proteins in a family descend from a common ancestor and typically have similar protein structure, three-dimensional structures, functions, and significant Sequence homology, sequence similarity. The most important of these is sequence similarity (usually amino-acid sequence), since it is the strictest indicator of homology and therefore the clearest indicator of common ancestry. A fairly well developed framework exists for evaluating the significance of similarity between a group of sequences using sequence alignment methods. Proteins that do not share a common ancestor are very unlikely to show statistically significant sequence similarity, making sequence alignment a powerf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MMP14
Matrix metalloproteinase-14 is an enzyme that in humans is encoded by the ''MMP14'' gene. Function Proteins of the matrix metalloproteinase (MMP) family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes, such as arthritis and metastasis. Deficits in MMP14 leads to premature aging, short lifespan, and cell senescence in mice, suggesting an important role of MMP14 in extracellular matrix remodeling during aging. Most MMP's are secreted as inactive pro-proteins which are activated when cleaved by extracellular proteinases. However, the protein encoded by this gene is a member of the ''membrane-type'' MMP (MT-MMP) subfamily; each member of this subfamily contains a potential transmembrane domain suggesting that these proteins are tethered to the cell surface rather than secreted. "This protein activates MMP2 protein, and this activity may be inv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PRG4
Proteoglycan 4 or lubricin is a proteoglycan that in humans is encoded by the ''PRG4'' gene. It acts as a joint/boundary lubricant. Function Lubricin is present in synovial fluid and on the surface (superficial layer) of articular cartilage and therefore plays an important role in joint lubrication and synovial homeostasis. When first isolated, cartilage lubricin was called "superficial zone protein" (SZP). Due to the discovery that the 32-kDa amino terminal fragment of lubricin could stimulate in-vitro megakaryocyte growth, the gene responsible for the expression of lubricin was initially called "megakaryocyte-stimulating factor" (MSF). However, Lubricin, MSF, and SZP are now collectively known as Proteoglycan 4 (hence PRG4 for the gene nomenclature). The evidence that lubricin is actually a proteoglycan is not solid. The expression of lubricin has also been detected and the protein localized in tendon, meniscus, lung, liver, heart, bone, ligament, muscle, and skin. It is pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MMP28
Matrix metalloproteinase 28 also known as epilysin is an enzyme that in humans is encoded by the ''MMP28'' gene. Function Matrix metalloproteinase 28, also known as epilysin, belongs to a family of proteins known as matrix metalloproteinases which are common to tissue regulation. Matrix metalloproteinases are commonly known to degrade the extracellular matrix, alongside regulating cell surface receptors MMP-28 releases growth factors and adhesion molecules to modulate inflammation. MMP-28 is unique in that it can be found in many regular tissues, denoting a potential role in maintaining the healthy structure and function of most tissue. MMPs commonly modulate their expression via negative and positive feedback loops as a result of releasing and responding to growth hormones. MMP-28 is less frequently found in tissues such as the brain, colon, heart, and lungs. However, MMP-28 is expressed heavily in organs such as the testes. Epilysin is also found in high concentration in basal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MMP27
Matrix metallopeptidase 27 also known as MMP-27 is an enzyme which in humans is encoded by the ''MMP27'' gene. Structure MMP-27 was discovered and cloned in 1998 by Yang and Kurkinen. Initially compared to the so-called Chicken MMP (CMMP), MMP-27 actually shows very little sequence homology with this protease. Sequence homology predicts that the human MMP-27 gene encodes the canonical domains shared by most MMPs (annotation based on Uniprot entry Q9H306): (i) a signal peptide (residues 1-17), (ii) a propeptide (18-98) containing the cysteine switch motif (89-96), (iii) a catalytic domain (99-263) containing the typical HEXXHXXGXXH motif of the metzincins (M10 and M12 families of the MEROPS database), (iv) a proline-rich hinge region (264-278) and (v) a hemopexin-like domain (279-465) folded as a four-bladed β-propeller through disulfide bond formation between the two flanking Cys residues (Cys279 and Cys465). MMP-27 could be classified in the stromelysin group of MMPs, since M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MMP25
Matrix metalloproteinase-25 is an enzyme that in humans is encoded by the ''MMP25'' gene. Proteins of the matrix metalloproteinase (MMP) family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes, such as arthritis and metastasis. Most MMPs are secreted as inactive proproteins which are activated when cleaved by extracellular proteinases. However, the protein encoded by this gene is a member of the membrane-type MMP (MT-MMP) subfamily, attached to the plasma membrane via a glycosylphosphatidyl inositol anchor. In response to bacterial infection or inflammation, the encoded protein is thought to inactivate alpha-1 proteinase inhibitor, a major tissue protectant against proteolytic enzymes released by activated neutrophils, facilitating the transendothelial migration of neutrophils to inflammatory sites. The encoded protein may also play a role in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MMP24
Matrix metalloproteinase-24 is an enzyme that in humans is encoded by the ''MMP24'' gene. Proteins of the matrix metalloproteinase Matrix metalloproteinases (MMPs), also known as matrix metallopeptidases or matrixins, are metalloproteinases that are calcium-dependent zinc-containing endopeptidases; other family members are adamalysins, serralysins, and astacins. The MMPs b ... (MMP) family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes, such as arthritis and metastasis. Most MMP's are secreted as inactive proproteins which are activated when cleaved by extracellular proteinases. However, the protein encoded by this gene is a member of the membrane-type MMP (MT-MMP) subfamily; each member of this subfamily contains a potential transmembrane domain suggesting that these proteins are expressed at the cell surface rather than secreted. This ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MMP21
Matrix metalloproteinase-21 (MMP-21) is an enzyme that in humans is encoded by the ''MMP21'' gene. Function This gene encodes a member of the matrix metalloproteinase family. Proteins in this family are involved in the breakdown of extracellular matrix for both normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, and disease processes, such as asthma and metastasis. The encoded protein may play an important role in embryogenesis, particularly in neuronal cells, as well as in lymphocyte development and survival. References Further reading * * * * * * * * External links * The MEROPS MEROPS is an online database for peptidases (also known as proteases, proteinases and proteolytic enzymes) and their inhibitors. The classification scheme for peptidases was published by Rawlings & Barrett in 1993, and that for protein inhibitor ... online database for peptidases and their inhibitorsM10.026 Matrix metalloproteinases EC 3.4. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MMP20
Matrix metalloproteinase-20 (MMP-20) also known as enamel metalloproteinase or enamelysin is an enzyme that in humans is encoded by the ''MMP20'' gene. Function Proteins of the matrix metalloproteinase ( MMP) family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes, such as arthritis and metastasis. Most MMP's are secreted as inactive proproteins which are activated when cleaved by extracellular proteinases. MMP-20, also known as enamelysin, appears to be the only MMP that is tooth-specific and it is expressed by cells of different developmental origin (i.e. epithelial ameloblasts and mesenchymal odontoblasts). Clinical significance The human MMP-20 gene contains 10 exons and is part of a cluster of matrix metalloproteinase genes that localize to human chromosome 11q22.3. A mutation in this gene, which alters the normal splice pattern and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MMP19
Matrix metalloproteinase-19 (MMP-19) also known as matrix metalloproteinase RASI is an enzyme that in humans is encoded by the ''MMP19'' gene. Function Proteins of the matrix metalloproteinase ( MMP) family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes, such as arthritis and metastasis. Most MMP's are secreted as inactive proproteins which are activated when cleaved by extracellular proteinases. This protein is expressed in human epidermis and endothelial cells and it has a role in cellular proliferation, migration, angiogenesis and adhesion. Multiple transcript variants encoding distinct isoforms have been identified for this gene. References Further reading * * * * * * * * * * * * * * * * * * External links * The MEROPS MEROPS is an online database for peptidases (also known as proteases, proteinases and proteolytic enzy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MMP17
Matrix metalloproteinase-17 (MMP-17) also known as membrane-type matrix metalloproteinase 4 (MT-MMP 4) is an enzyme that in humans is encoded by the ''MMP17'' gene. Function Proteins of the matrix metalloproteinase ( MMP) family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes, such as arthritis and metastasis. Most MMP's are secreted as inactive proproteins which are activated when cleaved by extracellular proteinases. The protein encoded by this gene is considered a member of the membrane-type MMP (MT-MMP) subfamily. MMP17 and MMP25 are to this day the only known GPI-anchored membrane-type MMPs, opposite to the more common transmembrane MMPs. The protein activates MMP2 by cleavage. In melanocytic cells MMP17 gene expression may be regulated by MITF. References Further reading * * * * * * * * * * * * * * * External links * The M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MMP16
Matrix metalloproteinase-16 is an enzyme that in humans is encoded by the ''MMP16'' gene. Proteins of the matrix metalloproteinase (MMP) family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes, such as arthritis and metastasis. Most MMP's are secreted as inactive proproteins which are activated when cleaved by extracellular proteinases. This gene produces at least two transcripts, one which encodes a membrane-bound form and another a soluble form of the protein. Both forms of the protein activate MMP2 by cleavage. This gene was once referred to as MT-MMP2, but was renamed as MT-MMP3 or MMP16. References Further reading * * * * * * * * * * * * * * * * * * External links * The MEROPS MEROPS is an online database for peptidases (also known as proteases, proteinases and proteolytic enzymes) and their inhibitors. The classification scheme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
