|
Matrix Metallopeptidase-9
Matrix metallopeptidase 9 (MMP-9), also known as 92 kDa type IV collagenase, 92 kDa gelatinase or gelatinase B (GELB), is a matrixin, a class of enzymes that belong to the zinc-metalloproteinases family involved in the degradation of the extracellular matrix. In humans the ''MMP9'' gene encodes for a signal peptide, a propeptide, a catalytic domain with inserted three repeats of fibronectin type II domain followed by a C-terminal hemopexin-like domain. 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, angiogenesis, bone development, wound healing, cell migration, learning and memory, as well as in pathological processes, such as arthritis, intracerebral hemorrhage, and metastasis. Most MMPs are secreted as inactive proproteins which are activated when cleaved by extracellular proteinases. The enzyme encoded by this gene degrades t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gelatinase B
Gelatinase B (, ''92-kDa gelatinase'', ''matrix metalloproteinase 9'', ''type V collagenase'', ''92-kDa type IV collagenase'', ''macrophage gelatinase'', ''95 kDa type IV collagenase/gelatinase'', ''collagenase IV'', ''collagenase type IV'', ''gelatinase MMP 9'', ''MMP 9'', ''type IV collagen metalloproteinase'') is an enzyme. This enzyme catalyses the following chemical reaction : Cleavage of gelatin types I and V and collagen types IV and V This enzyme is similar to gelatinase A, but possesses a further domain. Regarding its structure, Gelatinase B has domains which can bind with gelatin, laminin, and collagens type I and IV- collagenases do not possess these binding domains. Function Due to its role in cleaving collagen in the extracellular matrix, gelatinase B has multiple functional roles in normal physiology. Neutrophil action Gelatinase B, along with elastase, appears to be a regulatory factor in neutrophil migration across the basement membrane. Gelatinase B p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Learning
Learning is the process of acquiring new understanding, knowledge, behaviors, skills, values, attitudes, and preferences. The ability to learn is possessed by humans, animals, and some machines; there is also evidence for some kind of learning in certain plants. Some learning is immediate, induced by a single event (e.g. being burned by a hot stove), but much skill and knowledge accumulate from repeated experiences. The changes induced by learning often last a lifetime, and it is hard to distinguish learned material that seems to be "lost" from that which cannot be retrieved. Human learning starts at birth (it might even start before in terms of an embryo's need for both interaction with, and freedom within its environment within the womb.) and continues until death as a consequence of ongoing interactions between people and their environment. The nature and processes involved in learning are studied in many established fields (including educational psychology, neurop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basement Membrane
The basement membrane is a thin, pliable sheet-like type of extracellular matrix that provides cell and tissue support and acts as a platform for complex signalling. The basement membrane sits between epithelial tissues including mesothelium and endothelium, and the underlying connective tissue. Structure As seen with the electron microscope, the basement membrane is composed of two layers, the basal lamina and the reticular lamina. The underlying connective tissue attaches to the basal lamina with collagen VII anchoring fibrils and fibrillin microfibrils. The basal lamina layer can further be subdivided into two layers based on their visual appearance in electron microscopy. The lighter-colored layer closer to the epithelium is called the lamina lucida, while the denser-colored layer closer to the connective tissue is called the lamina densa. The electron-dense lamina densa layer is about 30–70 nanometers thick and consists of an underlying network of reticular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutrophil
Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying in different animals. They are formed from stem cells in the bone marrow and differentiated into subpopulations of neutrophil-killers and neutrophil-cagers. They are short-lived and highly mobile, as they can enter parts of tissue where other cells/molecules cannot. Neutrophils may be subdivided into segmented neutrophils and banded neutrophils (or bands). They form part of the polymorphonuclear cells family (PMNs) together with basophils and eosinophils. The name ''neutrophil'' derives from staining characteristics on hematoxylin and eosin ( H&E) histological or cytological preparations. Whereas basophilic white blood cells stain dark blue and eosinophilic white blood cells stain bright red, neutrophils stain a neutral pink. Normally, n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extracellular Matrix
In biology, the extracellular matrix (ECM), also called intercellular matrix, is a three-dimensional network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and biochemical support to surrounding cells. Because multicellularity evolved independently in different multicellular lineages, the composition of ECM varies between multicellular structures; however, cell adhesion, cell-to-cell communication and differentiation are common functions of the ECM. The animal extracellular matrix includes the interstitial matrix and the basement membrane. Interstitial matrix is present between various animal cells (i.e., in the intercellular spaces). Gels of polysaccharides and fibrous proteins fill the interstitial space and act as a compression buffer against the stress placed on the ECM. Basement membranes are sheet-like depositions of ECM on which various epithelial cells rest. Each type of conn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombospondins
Thrombospondins (TSPs) are a family of secreted glycoproteins with antiangiogenic functions. Due to their dynamic role within the extracellular matrix they are considered matricellular proteins. The first member of the family, thrombospondin 1 (THBS1), was discovered in 1971 by Nancy L. Baenziger. Types The thrombospondins are a family of multifunctional proteins. The family consists of thrombospondins 1-5 and can be divided into 2 subgroups: A, which contains TSP-1 and TSP-2, and B, which contains TSP-3, TSP-4 and TSP-5 (also designated cartilage oligomeric protein or COMP). TSP-1 and TSP-2 are homotrimers, consisting of three identical subunits, whereas TSP-3, TSP-4 and TSP-5 are homopentamers. TSP-1 and TSP-2 are produced by immature astrocytes during brain development, which promotes the development of new synapses. Thrombospondin 1 Thrombospondin 1 (TSP-1) is encoded by THBS1. It was first isolated from platelets that had been stimulated with thrombin, and so was design ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hematopoietic
Haematopoiesis (, from Greek , 'blood' and 'to make'; also hematopoiesis in American English; sometimes also h(a)emopoiesis) is the formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells. In a healthy adult person, approximately – new blood cells are produced daily in order to maintain steady state levels in the peripheral circulation.Semester 4 medical lectures at Uppsala University 2008 by Leif Jansson Process Haematopoietic stem cells (HSCs) Haematopoietic stem cells (HSCs) reside in the medulla of the bone ( bone marrow) and have the unique ability to give rise to all of the different mature blood cell types and tissues. HSCs are self-renewing cells: when they differentiate, at least some of their daughter cells remain as HSCs so the pool of stem cells is not depleted. This phenomenon is called asymmetric division. The other daughters of HSCs ( myeloid and lymphoid progenitor cells) can follow any of the ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interleukin 8
Interleukin 8 (IL-8 or chemokine (C-X-C motif) ligand 8, CXCL8) is a chemokine produced by macrophages and other cell types such as epithelial cells, airway smooth muscle cells and endothelial cells. Endothelial cells store IL-8 in their storage vesicles, the Weibel-Palade bodies. In humans, the interleukin-8 protein is encoded by the ''CXCL8'' gene. IL-8 is initially produced as a precursor peptide of 99 amino acids which then undergoes cleavage to create several active IL-8 isoforms. In culture, a 72 amino acid peptide is the major form secreted by macrophages. There are many receptors on the surface membrane capable of binding IL-8; the most frequently studied types are the G protein-coupled serpentine receptors CXCR1 and CXCR2. Expression and affinity for IL-8 differs between the two receptors (CXCR1 > CXCR2). Through a chain of biochemical reactions, IL-8 is secreted and is an important mediator of the immune reaction in the innate immune system response. Function ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collagen
Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole-body protein content. Collagen consists of amino acids bound together to form a triple helix of elongated fibril known as a collagen helix. It is mostly found in connective tissue such as cartilage, bones, tendons, ligaments, and skin. Depending upon the degree of mineralization, collagen tissues may be rigid (bone) or compliant (tendon) or have a gradient from rigid to compliant (cartilage). Collagen is also abundant in corneas, blood vessels, the gut, intervertebral discs, and the dentin in teeth. In muscle tissue, it serves as a major component of the endomysium. Collagen constitutes one to two percent of muscle tissue and accounts for 6% of the weight of the skeletal muscle tissue. The fibroblast is the most common cell tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proteinase
A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. They do this by cleaving the peptide bonds within proteins by hydrolysis, a reaction where water breaks bonds. Proteases are involved in many biological functions, including digestion of ingested proteins, protein catabolism (breakdown of old proteins), and cell signaling. In the absence of functional accelerants, proteolysis would be very slow, taking hundreds of years. Proteases can be found in all forms of life and viruses. They have independently evolved multiple times, and different classes of protease can perform the same reaction by completely different catalytic mechanisms. Hierarchy of proteases Based on catalytic residue Proteases can be classified into seven broad groups: * Serine pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proprotein
A protein precursor, also called a pro-protein or pro-peptide, is an inactive protein (or peptide) that can be turned into an active form by post-translational modification, such as breaking off a piece of the molecule or adding on another molecule. The name of the precursor for a protein is often prefixed by ''pro-''. Examples include proinsulin and proopiomelanocortin, which are both prohormones. Protein precursors are often used by an organism when the subsequent protein is potentially harmful, but needs to be available on short notice and/or in large quantities. Enzyme precursors are called zymogens or proenzymes. Examples are enzymes of the digestive tract in humans. Some protein precursors are secreted from the cell. Many of these are synthesized with an N-terminal signal peptide that targets them for secretion. Like other proteins that contain a signal peptide, their name is prefixed by ''pre''. They are thus called pre-pro-proteins or pre-pro-peptides. The signal peptide is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metastasis
Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, then, are metastases (mets). It is generally distinguished from cancer invasion, which is the direct extension and penetration by cancer cells into neighboring tissues. Cancer occurs after cells are genetically altered to proliferate rapidly and indefinitely. This uncontrolled proliferation by mitosis produces a primary heterogeneic tumour. The cells which constitute the tumor eventually undergo metaplasia, followed by dysplasia then anaplasia, resulting in a malignant phenotype. This malignancy allows for invasion into the circulation, followed by invasion to a second site for tumorigenesis. Some cancer cells known as circulating tumor cells acquire the ability to penetrate the walls of lymphatic or blood vessels, after which they a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.svg "Click for more on -> Collagen")
