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Endosomal
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 dissocia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RAB7A
Ras-related protein Rab-7a is a protein that in humans is encoded by the ''RAB7A'' gene. Ras-related protein Rab-7a is involved in endocytosis, which is a process that brings substances into a cell. The process of endocytosis works by folding the cell membrane around a substance outside of the cell (for example a protein) and then forms a Vesicle (biology and chemistry), vesicle. The vesicle is then brought into the cell and cleaved from the cell membrane. RAB7A plays an important role in the movement of vesicles into the cell as well as with vesicle trafficking. Various mutations of RAB7A are associated with HSAN Type I, Hereditary sensory neuropathy type 1C (HSN IC), also known as Charcot-Marie-Tooth disease, Charcot-Marie-Tooth syndrome type 2B (CMT2B). Function Members of the Rab (G-protein), RAB family of RAS-related GTP-binding proteins are important regulators of vesicular transport and are located in specific intracellular compartments. RAB7 has been localized to lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EEA1
The gene EEA1 encodes for the 1400 amino acid protein, Early Endosome Antigen 1. EEA1 localizes exclusively to early endosomes and has an important role in endosomal trafficking. EEA1 binds directly to the phospholipid phosphatidylinositol 3-phosphate through its C-terminal FYVE domain and forms a homodimer through a coiled coil. EEA1 acts as a tethering molecule that couples vesicle docking with SNARE (protein), SNAREs such as N-ethylmaleimide sensitive fusion protein, bringing the endosomes physically closer and ultimately resulting in the fusion and delivery of endosomal cargo. Function EEA1 is a RAB5A effector protein which binds via an N-terminal zinc finger domain and is required for fusion of early and late endosomes and for sorting at the early endosome level. EEA1 plays a role in endocytosis and is recruited by Rab5-GTP to endosomal membranes. EEA1 may be regulated through monoubiquination, affecting endosome fusion and trafficking. Ubiquitin selective segregase p97 m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocytic Cycle
Endocytosis is a cellular process in which 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 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 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 virtually all cells and form domains of the plasma membrane termed cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
V-ATPase
Vacuolar-type ATPase (V-ATPase) is a highly conserved evolutionarily ancient enzyme with remarkably diverse functions in eukaryotic organisms. V-ATPases acidify a wide array of intracellular organelles and pump protons across the plasma membranes of numerous cell types. V-ATPases couple the energy of ATP hydrolysis to proton transport across intracellular and plasma membranes of eukaryotic cells. It is generally seen as the polar opposite of ATP synthase because ATP synthase is a proton channel that uses the energy from a proton gradient to produce ATP. V-ATPase however, is a proton pump that uses the energy from ATP hydrolysis to produce a proton gradient. The Archaea-type ATPase (A-ATPase) is a related group of ATPases found in archaea that often work as an ATP synthase. It forms a clade V/A-ATPase with V-ATPase. Most members of either group shuttle protons (), but a few members have evolved to use sodium ions () instead. Roles played by V-ATPases V-ATPases are foun ... [...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] |
LDL Receptor
The low-density lipoprotein receptor (LDL-R) is a mosaic protein of 839 amino acids (after removal of 21-amino acid signal peptide) that mediates the endocytosis of cholesterol-rich low-density lipoprotein (LDL). It is a cell-surface receptor that recognizes apolipoprotein B100 (ApoB100), which is embedded in the outer phospholipid layer of very low-density lipoprotein (VLDL), their remnants—i.e. intermediate-density lipoprotein (IDL), and LDL particles. The receptor also recognizes apolipoprotein E (ApoE) which is found in chylomicron remnants and IDL. In humans, the LDL receptor protein is encoded by the gene on chromosome 19. It belongs to the low density lipoprotein receptor gene family. It is most significantly expressed in bronchial epithelial cells and adrenal gland and cortex tissue. Michael S. Brown and Joseph L. Goldstein were awarded the 1985 Nobel Prize in Physiology or Medicine for their identification of LDL-R and its relation to cholesterol metaboli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HeLa Cell Endocytic Pathway Labeled For EGFR And Transferrin
HeLa () is an immortalized cell line used in scientific research. It is the oldest human cell line and one of the most commonly used. HeLa cells are durable and prolific, allowing for extensive applications in scientific study. The line is derived from cervical cancer cells taken on February 8, 1951, from Henrietta Lacks, a 31-year-old African American mother of five, after whom the line is named. Lacks died of cancer on October 4, 1951. The cells from Lacks's cancerous cervical tumor were taken without her knowledge, which was common practice in the United States at the time. Cell biologist George Otto Gey found that they could be kept alive, and developed a cell line. Previously, cells cultured from other human cells would survive for only a few days, but cells from Lacks's tumor behaved differently. History Origin In 1951, Henrietta Lacks was admitted to the Johns Hopkins Hospital with symptoms of irregular vaginal bleeding; she was subsequently treated for cervical c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transferrin
Transferrins are glycoproteins found in vertebrates which bind and consequently mediate the transport of iron (Fe) through blood plasma. They are produced in the liver and contain binding sites for two Iron(III), Fe3+ ions. Human transferrin is encoded by the ''TF'' gene and produced as a 76 Dalton (unit), kDa glycoprotein. Transferrin glycoproteins bind iron tightly, but reversibly. Although iron bound to transferrin is less than 0.1% (4 mg) of total body iron, it forms the most vital iron pool with the highest rate of turnover (25 mg/24 h). Transferrin has a molecular weight of around 80 atomic mass unit, kDa and contains two specific high-affinity Fe(III) binding sites. The affinity of transferrin for Fe(III) is extremely high (association constant is 1020 M−1 at pH 7.4) but decreases progressively with decreasing pH below neutrality. Transferrins are not limited to only binding to iron but also to different metal ions. These glycoproteins are located in various b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transferrin Receptor
Transferrin receptor (TfR) is a carrier protein for transferrin. It is needed for the import of iron into cells and is regulated in response to intracellular iron concentration. It imports iron by internalizing the transferrin-iron complex through receptor-mediated endocytosis.Figure 3: The cycle of transferrin and transferrin receptor 1-mediated cellular iron uptake./ref> The existence of a receptor for transferrin iron uptake has been recognized since the late 1950s. Earlier two transferrin receptors in humans, transferrin receptor 1 and transferrin receptor 2 had been characterized and until recently cellular iron uptake was believed to occur chiefly via these two well documented transferrin receptors. Both these receptors are transmembrane glycoproteins. TfR1 is a high affinity ubiquitously expressed receptor while expression of TfR2 is restricted to certain cell types and is unaffected by intracellular iron concentrations. TfR2 binds to transferrin with a 25-30 fold lower aff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid
Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries, and in nanotechnology. Lipids are broadly defined as hydrophobic or amphiphilic small molecules; the amphiphilic nature of some lipids allows them to form structures such as vesicles, multilamellar/ unilamellar liposomes, or membranes in an aqueous environment. Biological lipids originate entirely or in part from two distinct types of biochemical subunits or "building-blocks": ketoacyl and isoprene groups. Using this approach, lipids may be divided into eight categories: fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, saccharolipids, and polyketides (derived from condensatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transferrin Receptor
Transferrin receptor (TfR) is a carrier protein for transferrin. It is needed for the import of iron into cells and is regulated in response to intracellular iron concentration. It imports iron by internalizing the transferrin-iron complex through receptor-mediated endocytosis.Figure 3: The cycle of transferrin and transferrin receptor 1-mediated cellular iron uptake./ref> The existence of a receptor for transferrin iron uptake has been recognized since the late 1950s. Earlier two transferrin receptors in humans, transferrin receptor 1 and transferrin receptor 2 had been characterized and until recently cellular iron uptake was believed to occur chiefly via these two well documented transferrin receptors. Both these receptors are transmembrane glycoproteins. TfR1 is a high affinity ubiquitously expressed receptor while expression of TfR2 is restricted to certain cell types and is unaffected by intracellular iron concentrations. TfR2 binds to transferrin with a 25-30 fold lower aff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrophage
Macrophages (; abbreviated MPhi, φ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that are specific to healthy body cells on their surface. This self-protection method can be contrasted with that employed by Natural killer cell, Natural Killer cells. This process of engulfment and digestion is called phagocytosis; it acts to defend the host against infection and injury. Macrophages are found in essentially all tissues, where they patrol for potential pathogens by amoeboid movement. They take various forms (with various names) throughout the body (e.g., histiocytes, Kupffer cells, alveolar macrophages, microglia, and others), but all are part of the mononuclear phagocyte system. Besides phagocytosis, they play a critical role in nonspecific defense (innate immunity) and also help initiate specific defense mechanisms (adapti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
