Connective tissue extracellular matrix elastin

Fibrillin microfibrils are widely distributed extracellular matrix assemblies that endow elastic and non elastic connective tissues with long-range elasticity. They direct tropoelastin deposition during elastic fibrillogenesis and form an outer mantle for mature elastic fibers. Microfibril arrays are also abundant in dynamic tissues that do not express elastin, such as the ciliary zonules of the eye. Mutations in fibrillin-1—the principal structural component of microfibrils—cause Marfan syndrome, a heritable disease with severe aortic, ocular, and skeletal defects. Isolated fibrillin-rich microfibrils have a complex 56 nm beads-on-a-string appearance the molecular basis of their assembly and... 

These serine proteases are used to remove pathogens by their hydrolytic activity. They degrade cell membrane proteins and connective tissue matrices by hydrolysis of extracellular matrix proteins such as fibronectin, type IV collagen and laminin, or solubilizing fibrous elastins [55, 56]. Immune cell proteases also are capable of cleaving cytokines, growth hormone, neuropeptides, and procoagulant proteins such as Factors X and V. 

Connective Tissue Formation. Protein-lysine 6-oxidase (lysyl oxidase) is a cuproenzyme that is essential for stabilization of extracellular matrixes, specifically the enzymatic cross-linking of collagen and elastin. Complex mechanisms involve the deamination of lysine and hydrolysine residues at specific extracellular sites. The enzyme is highly associated with connective tissue and located in the aorta, dermal con-... 

Proteoglycan aggregates are typically found in the extracellular matrix of connective tissue. The noncovalent attachment of each proteoglycan to hyaluronic acid via the core protein is mediated by two linker proteins (not shown). Proteoglycans interact with numerous fibrous proteins in the extracellular matrix such as collagen, elastin, and fibronectin (a glycoprotein involved in cell adhesion). 

Connective tissue, such as tendon and cartilage, differs from other solid tissues In that most of Its volume Is made up of extracellular matrix rather than cells. This matrix Is packed with Insoluble protein fibers and contains proteoglycans, various multladhesive proteins, and hyaluronan, a very large, nonsulfated GAG. The most abundant fibrous protein In connective tissue Is collagen. Rubberlike elastin fibers, which can be stretched and relaxed, also are present In deformable sites (e.g., skin, tendons, heart). As discussed later, the fibronectins, a family of multladhesive matrix proteins, form their own distinct fibrils In the matrix of some connective tissues. Although several types of cells are found In connective tissues, the various ECM components are produced largely by cells called fibroblasts. 

Connective tissue, which consists primarily of fibroblasts, produces extracellular matrix materials that surround cells and tissues, determining their appropriate position within the organ (see Chapter 49). These materials include structural proteins (collagen and elastin), adhesive proteins (fibronectin), and glycosaminoglycans (heparan sulfate, chondroitin sulfate). The unique structures of the proteins and carbohydrates found within the extracellular matrix allow tissues and organs to carry out their many functions. A loss of these supportive and barrier functions of connective tissue sometimes leads to significant clinical consequences, such as those that result from the microvascular alterations that lead to blindness or renal failure, or peripheral neuropathies in patients with diabetes mellitus. 

ELRs are a promising model of biocompatible protein-based polymers. The basic structure of ELRs involves a repeating sequence based on the recurring sequences found in the mammalian elastic protein elastin [4]. As far as their properties are concerned, some of their main characteristics are derived from those of the natural protein. Elastin is an extracellular matrix protein that is present in aU vertebrate connective tissue. Its functions include the provision of elasticity and resilience to tissues, such as large elastic blood vessels (aorta), elastic ligaments, lung and skin, which are subjected to repetitive and reversible deformation [5, 6]. 

Elastin is an insoluble, pol5mieric, extracellular matrix protein that provides the connective tissue in the body (skin, lungs, ligaments. 

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