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Insulin-like Growth Factor 2 Receptor
Insulin-like growth factor 2 receptor (IGF2R), also called the cation-independent mannose-6-phosphate receptor (CI-MPR) is a protein that in humans is encoded by the ''IGF2R'' gene. IGF2R is a multifunctional protein receptor that binds insulin-like growth factor 2 (IGF2) at the cell surface and mannose-6-phosphate (M6P)-tagged proteins in the ''trans''- Golgi network. Structure The structure of the IGF2R is a type I transmembrane protein (that is, it has a single transmembrane domain with its C-terminus on the cytoplasmic side of lipid membranes) with a large extracellular/lumenal domain and a relatively short cytoplasmic tail. The extracellular domain consists of a small region homologous to the collagen-binding domain of fibronectin and of fifteen repeats of approximately 147 amino acid residues. Each of these repeats is homologous to the 157-residue extracytoplasmic domain of the mannose 6-phosphate receptor. Binding to IGF2 is mediated through one of the repeats, ... [...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 residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 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 pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid Hydrolase
An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen cation, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid. The first category of acids are the proton donors, or Brønsted–Lowry acids. In the special case of aqueous solutions, proton donors form the hydronium ion H3O+ and are known as Arrhenius acids. Brønsted and Lowry generalized the Arrhenius theory to include non-aqueous solvents. A Brønsted–Lowry or Arrhenius acid usually contains a hydrogen atom bonded to a chemical structure that is still energetically favorable after loss of H+. Aqueous Arrhenius acids have characteristic properties that provide a practical description of an acid. Acids form aqueous solutions with a sour taste, can turn blue litmus red, and react with bases and certain metals (like calcium) to form salts. The word ''acid'' is derived from the Latin , meaning 'sour'. An aqueous solution of an ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mannose 6-phosphate Receptor
The mannose 6-phosphate receptors (MPRs) are transmembrane glycoproteins that target enzymes to lysosomes in vertebrates. Mannose 6-phosphate receptors bind newly synthesized lysosomal hydrolases in the trans-Golgi network (TGN) and deliver them to pre-lysosomal compartments. There are two different MPRs, one of ~300kDa and a smaller, dimeric receptor of ~46kDa. The larger receptor is known as the cation-independent mannose 6-phosphate receptor ( CI-MPR), while the smaller receptor ( CD-MPR) requires divalent cations to efficiently recognize lysosomal hydrolases. While divalent cations are not essential for ligand binding by the human CD-MPR, the nomenclature has been retained. Both of these receptors bind terminal mannose 6-phosphate with similar affinity (CI-MPR = 7 μM, CD-MPR = 8 μM) and have similar signals in their cytoplasmic domains for intracellular trafficking. History Elizabeth Neufeld was studying patients who had multiple inclusion bodies present in their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IGF-1 Receptor
The insulin-like growth factor 1 (IGF-1) receptor is a protein found on the surface of human cells. It is a transmembrane receptor that is activated by a hormone called insulin-like growth factor 1 (IGF-1) and by a related hormone called IGF-2. It belongs to the large class of tyrosine kinase receptors. This receptor mediates the effects of IGF-1, which is a polypeptide protein hormone similar in molecular structure to insulin. IGF-1 plays an important role in growth and continues to have anabolic effects in adults – meaning that it can induce hypertrophy of skeletal muscle and other target tissues. Mice lacking the IGF-1 receptor die late in development, and show a dramatic reduction in body mass. This testifies to the strong growth-promoting effect of this receptor. Structure Two alpha subunits and two beta subunits make up the IGF-1 receptor. Both the α and β subunits are synthesized from a single mRNA precursor. The precursor is then glycosylated, proteolytically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cluster Of Differentiation
The cluster of differentiation (also known as cluster of designation or classification determinant and often abbreviated as CD) is a protocol used for the identification and investigation of cell surface molecules providing targets for immunophenotyping of cells. In terms of physiology, CD molecules can act in numerous ways, often acting as receptors or ligands important to the cell. A signal cascade is usually initiated, altering the behavior of the cell (see cell signaling). Some CD proteins do not play a role in cell signaling, but have other functions, such as cell adhesion. CD for humans is numbered up to 371 (). Nomenclature The CD nomenclature was proposed and established in the 1st International Workshop and Conference on Human Leukocyte Differentiation Antigens (HLDA), held in Paris in 1982. This system was intended for the classification of the many monoclonal antibodies (mAbs) generated by different laboratories around the world against epitopes on the surface mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M6PRBP1
Mannose-6-phosphate receptor binding protein 1 (M6PRBP1) is a protein which in humans is encoded by the ''M6PRBP1'' gene. Its gene product, as well as the gene itself, is commonly known as TIP47. Function Mannose 6-phosphate receptors (MPRs) deliver lysosomal hydrolase from the Golgi to endosomes and then return to the Golgi complex. The protein encoded by this gene interacts with the cytoplasmic domains of both cation-independent and cation-dependent MPRs, and is required for endosome-to-Golgi transport. This protein also binds directly to the GTPase RAB9 ( RAB9A), a member of the RAS oncogene family. The interaction with RAB9 has been shown to increase the affinity of this protein for its cargo. The mannose-6-phosphate receptor-binding properties of TIP47 are disputed, despite the designation of M6PRBP1 as TIP47's gene symbol. TIP47 protein is most commonly described in the scientific literature as a coat protein for lipid droplets. TIP47 belongs to the peripilin protei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retromer
Retromer is a complex of proteins that has been shown to be important in recycling transmembrane receptors from endosomes to the ''trans''-Golgi network (TGN) and directly back to the plasma membrane. Mutations in retromer and its associated proteins have been linked to Alzheimer's and Parkinson's diseases. Retromer is a heteropentameric complex, which in humans is composed of a less defined membrane-associated sorting nexin dimer ( SNX1, SNX2, SNX5, SNX6), and a vacuolar protein sorting (Vps) heterotrimer containing Vps26, Vps29, and Vps35. Although the SNX dimer is required for the recruitment of retromer to the endosomal membrane, the cargo binding function of this complex is contributed by the core heterotrimer through the binding of Vps26 and Vps35 subunits to various cargo molecules including M6PR, wntless, SORL1 (which is also a receptor for other cargo proteins such as APP), and sortilin. Early study on sorting of acid hydrolases such as carboxypeptidase Y (C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endosome
Endosomes are a collection of intracellular sorting organelles in eukaryotic cells. They are parts of the endocytic membrane transport pathway originating from the trans Golgi network. Molecules or ligands internalized from the plasma membrane can follow this pathway all the way to lysosomes for degradation or can be recycled back to the cell membrane in the endocytic cycle. Molecules are also transported to endosomes from the trans Golgi network and either continue to lysosomes or recycle back to the Golgi apparatus. Endosomes can be classified as early, sorting, or late depending on their stage post internalization. Endosomes represent a major sorting compartment of the endomembrane system in cells. Function Endosomes provide an environment for material to be sorted before it reaches the degradative lysosome. For example, low-density lipoprotein (LDL) is taken into the cell by binding to the LDL receptor at the cell surface. Upon reaching early endosomes, the LDL dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GGA1
ADP-ribosylation factor-binding protein GGA1 is a protein that in humans is encoded by the ''GGA1'' gene. This gene encodes a member of the Golgi-localized, gamma adaptin ear-containing, ARF-binding (GGA) protein family. Members of this family are ubiquitous coat proteins that regulate the trafficking of proteins between the trans-Golgi network and the lysosome. These proteins share an amino-terminal VHS domain which mediates sorting of the mannose 6-phosphate receptors at the trans-Golgi network. They also contain a carboxy-terminal region with homology to the ear domain of gamma-adaptins. Multiple alternatively spliced transcript variants encoding different isoforms have been found for this gene. Interactions GGA1 has been shown to interact with Sortilin 1, BACE2, RABEP1 Rab GTPase-binding effector protein 1 is an enzyme that in humans is encoded by the ''RABEP1'' gene. It belongs to rabaptin protein family. Interactions RABEP1 has been shown to interact with: * A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumen (anatomy)
In biology, a lumen (: lumina) is the inside space of a tubular structure, such as an artery or intestine. It comes . It can refer to: *the interior of a vessel, such as the central space in an artery, vein or capillary through which blood flows *the interior of the gastrointestinal tract *the pathways of the bronchi in the lungs *the interior of renal tubules and urinary collecting ducts *the pathways of the female genital tract, starting with a single pathway of the vagina, splitting up in two lumina in the uterus, both of which continue through the fallopian tubes *the fluid-filled cavity forming in the blastocyst during pre-implantation development called the blastocoel In cell biology, lumen is a membrane-defined space that is found inside several organelles, cellular components, or structures, including thylakoid, endoplasmic reticulum, Golgi apparatus, lysosome, mitochondrion, and microtubule. Transluminal procedures ''Transluminal procedures'' are procedures occur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocytosis
Endocytosis is a cellular process in which Chemical substance, substances are brought into the cell. The material to be internalized is surrounded by an area of cell membrane, which then buds off inside the cell to form a Vesicle (biology and chemistry), vesicle containing the ingested materials. Endocytosis includes pinocytosis (cell drinking) and phagocytosis (cell eating). It is a form of active transport. History The term was proposed by Christian de Duve, De Duve in 1963. Phagocytosis was discovered by Élie Metchnikoff in 1882. Pathways Endocytosis pathways can be subdivided into four categories: namely, receptor-mediated endocytosis (also known as clathrin-mediated endocytosis), caveolae, pinocytosis, and phagocytosis. * Clathrin-mediated endocytosis is mediated by the production of small (approx. 100 nm in diameter) vesicles that have a morphologically characteristic coat made up of the cytosolic protein clathrin. Clathrin-coated vesicles (CCVs) are found in vir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
