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Laminin, Alpha 2
Laminin subunit alpha-2 is a protein that in humans is encoded by the ''LAMA2'' gene. Function Laminin, an extracellular matrix protein, is a major component of the basement membrane. It is thought to mediate the attachment, migration, and organization of cells into tissues during embryonic development by interacting with other extracellular matrix components. It is composed of three subunits, alpha, beta, and gamma, which are bound to each other by disulfide bonds into a cross-shaped molecule. This gene encodes the alpha 2 chain, which constitutes one of the subunits of laminin 2 (merosin) and laminin 4 (s-merosin). Mutations in this gene have been identified as the cause of congenital merosin-deficient muscular dystrophy. Two transcript variants encoding different proteins have been found for this gene. References Further reading * * * * * * * * * * * * * * * * External links GeneReviews/NCBI/NIH/UW entry on Congenital Muscular Dystrophy Overview* LOVD The Leiden Open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laminin
Laminins are a family of glycoproteins of the extracellular matrix of all animals. They are major components of the basal lamina (one of the layers of the basement membrane), the protein network foundation for most cells and organs. The laminins are an important and biologically active part of the basal lamina, influencing cell differentiation, migration, and adhesion. Laminins are heterotrimeric proteins with a high molecular mass (~400 to ~900 kDa). They contain three different chains (α, β and γ) encoded by five, four, and three paralogous genes in humans, respectively. The laminin molecules are named according to their chain composition. Thus, laminin-511 contains α5, β1, and γ1 chains. Fourteen other chain combinations have been identified ''in vivo''. The trimeric proteins intersect to form a cross-like structure that can bind to other cell membrane and extracellular matrix molecules. The three shorter arms are particularly good at binding to other laminin molecules, ... [...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 fluid, 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 ... [...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 Epithelium, 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 microscope, electron-dense lamina densa layer is about 30–70 nanometers thick and consists of an underlying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congenital Muscular Dystrophy
Congenital muscular dystrophies are autosomal recessively-inherited muscle diseases. They are a group of heterogeneous disorders characterized by muscle weakness which is present at birth and the different changes on muscle biopsy that ranges from myopathic to overtly dystrophic due to the age at which the biopsy takes place.update 2012 Signs and symptoms Most infants with CMD will display some progressive muscle weakness or muscle wasting (atrophy), although there can be different degrees and symptoms of severeness of progression. The weakness is indicated as ''hypotonia'', or lack of muscle tone, which can make an infant seem unstable. Children may be slow with their motor skills; such as rolling over, sitting up or walking, or may not even reach these milestones of life. Some of the rarer forms of CMD can result in significant learning disabilities. Genetics Congenital muscular dystrophies (CMDs) are autosomal recessively inherited, except in some cases of de novo ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LOVD
The Leiden Open Variation Database (LOVD) is a free, flexible web-based open source database developed in the Leiden University Medical Center in the Netherlands, designed to collect and display variants in the DNA sequence. The focus of an LOVD is usually the combination between a gene and a genetic (heritable) disease. All sequence variants found in individuals are collected in the database, together with information about whether they could be causally connected to the disease (i.e. a disease-causing variant or mutation) or not (i.e. a non-disease causing variant). Specialized doctors (clinical geneticists) use LOVDs to diagnose and advise patients carrying a genetic disease. Ideally, if a patient has been screened for mutations and one has been found, information in LOVD can predict the progress of the disease. In contrast to human genome databases, showing information on all DNA variants, LOVDs include information about the individuals in which the variants were found. This pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
