Ursharona's List: cell biology

• Fibronectin
• glycoprotein of the extracellular matrix that
• binds to
• membrane-spanning receptor proteins called integrins
• binds extracellular matrix components such as collagen, fibrin and heparan sulfate proteoglycans (e.g. syndecans).
• two nearly identical monomers linked by a pair of disulfide bonds.
• Two types of fibronectin are present in vertebrates:
• soluble plasma fibronectin (
• major protein component of blood plasma (300 μg/ml) and is produced in the liver by hepatocytes.
• insoluble cellular fibronectin is a major component of the extracellular matrix. It is secreted by various cells, primarily fibroblasts, as a soluble protein dimer and is then assembled into an insoluble matrix in a complex cell-mediated process.
• Fibronectin plays a major role in cell adhesion, growth, migration and differentiation, and it is important for processes such as wound healing and embryonic development.
• Altered fibronectin expression, degradation, and organization has been associated with a number of pathologies, including cancer and fibrosis.
• • review molecular weights at some pt 

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• Listeria is a bacterial genus that contains seven species. Named after the English pioneer of sterile surgery Joseph Lister,
• Listeriosis is a serious disease for humans; the overt form of the disease has a mortality rate of about 20 percent. The two main clinical manifestations are sepsis and meningitis. Meningitis is often complicated by encephalitis, a pathology that is unusual for bacterial infections.
• Listeria
• induces directed polymerization of actin by the ActA transmembrane protein,
• majority of Listeria bacteria are targeted by the immune system before they are able to cause infection
• Listeria, inventively, polymerizes an actin tail or "comet",^[10] from actin monomers in the host's cytoplasm
• Gelsolin, an actin filament severing protein, localizes at the tail of Listeria and accelerates the bacterium's motility
• list of foods that have sometimes caused outbreaks of Listeria: hot dogs, deli meats, pasteurized or unpasteurized milk, cheeses (particularly soft-ripened cheeses like feta, Brie, Camembert, blue-veined, or Mexican-style queso blanco), raw and cooked poultry, raw meats, ice cream, raw vegetables, and raw and smoked fish.
• Alcohol is an effective topical sanitizer against Listeria.
• Antibiotics effective against Listeria species include ampicillin, vancomycin (unclear effectiveness), ciprofloxacin, linezolid, and azithromycin.

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• NBD dimer consists of two ATP binding pockets

• Microtubules are filaments of the cytoskeleton. They typically form through the polymerization of α- and β-tubulin dimers elongating existing microtubules.
• Microtubules can also nucleate in the cytoplasm, forming so-called astral microtubules radiating star-like from a diffusible nucleation center.

• Human hair is approximately 14% cysteine
• pungent smells of burning hair and rubber are due to the sulfur compounds formed

• • vitamin type III IF found in all metazoans important in HIV
• N-terminal "head domain" binds DNA.^[
• Phosphorylation of the head region can affect filament stability
• The anti-parallel orientation of tetramers means that, unlike microtubules and microfilaments, which have a plus end and a minus end, IFs lack polarity.
• Also, as opposed to actin or tubulin, intermediate filaments
• do not contain a binding site for a nucleoside triphosphate.
• do not undergo treadmilling like microtubules and actin fibers, but they are dynamic
• can be stretched several times their initial length

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• A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen,^[1] the structural framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals.

• Fibrillin is a glycoprotein, which is essential for the formation of elastic fibers found in connective tissue.
• Fibrillin is secreted into the extracellular matrix by fibroblasts and becomes incorporated into the insoluble microfibrils, which appear to provide a scaffold for deposition of elastin.

• the cristae space (formed by infoldings of the inner membrane)
• The outer mitochondrial membrane, which encloses the entire organelle, has a protein-to-phospholipid ratio similar to that of the eukaryotic plasma membrane
• contains large numbers of integral proteins called porins.
• Disruption of the outer membrane permits proteins in the intermembrane space to leak into the cytosol, leading to certain cell death.
• mitochondrial outer membrane can associate with the endoplasmic reticulum (ER) membrane, in a structure called MAM (mitochondria-associated ER-membrane
• important in the ER-mitochondria calcium signaling and involved in the transfer of lipids between the ER and mitochondria
• The inner mitochondrial membrane contains proteins with five types of functions
• • Those that perform the redox reactions of oxidative phosphorylation
   
  • ATP synthase, which generates ATP in the matrix
   
  • Specific transport proteins that regulate metabolite passage into and out of the matrix
   
  • Protein import machinery.
   
  • Mitochondria fusion and fission protein
• ontains more than 151 different polypeptides, and has a very high protein-to-phospholipid ratio (more than 3:1 by weight, which is about 1 protein for 15 phospholipids
• The inner membrane is home to around 1/5 of the total protein in a mitochondrion
• In addition, the inner membrane is rich in an unusual phospholipid, cardiolipin
• membrane potential across the inner membrane, formed by the action of the enzymes of the electron transport chain.
• cristae, which expand the surface area of the inner mitochondrial membrane, enhancing its ability to produce ATP
• The matrix is the space enclosed by the inner membrane. It contains about 2/3 of the total protein in a mitochondrion.
• matrix is important in the production of ATP with the aid of the ATP synthase contained in the inner membran
• matrix contains a highly-concentrated mixture of hundreds of enzymes, special mitochondrial ribosomes, tRNA, and several copies of the mitochondrial DNA genome
• major functions include oxidation of pyruvate and fatty acids, and the citric acid cycle.^[6]

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• Cardiolipin (IUPAC name "1,3-bis(sn-3’-phosphatidyl)-sn-glycerol") is an important component of the inner mitochondrial membrane, where it constitutes about 20% of the total lipid composition.
• only other place that cardiolipin can be found is in the membranes of most bacteria
• he name ‘cardiolipin’ is derived from the fact that it was first found in animal hearts
• exclusively in the inner mitochondrial membrane where it is essential for the optimal function of numerous enzymes that are involved in mitochondrial energy metabolism

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• The cisternae stack has four functional regions: the cis-Golgi network, medial-Golgi, endo-Golgi, and trans-Golgi network.
• Vesicles from the endoplasmic reticulum (via the vesicular-tubular clusters) fuse with the network and subsequently progress through the stack to the trans Golgi network, where they are packaged and sent to the required destination
• The phosphorylation of molecules requires that ATP is imported into the lumen of the Golgi^[15] and then utilised by resident kinases

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• Cystic fibrosis transmembrane conductance regulator
• • class II ER associated degradation related disease
• CFTR is a ABC transporter-class ion channel that transports chloride and thiocyanate^[3] ions across epithelial cell membranes.
• Mutations of the CFTR gene affect functioning of the chloride ion channels in these cell membranes, leading to cystic fibrosis and congenital absence of the vas deferens.

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• Ubiquitin can be attached to proteins and label them for destruction. The ubiquitin tag directs proteins to the proteasome, which is a large protein complex in the cell that degrades and recycles unneeded proteins. This discovery won the Nobel Prize for chemistry in 2004.

• Endoplasmic-reticulum-associated protein degradation (ERAD) designates a cellular pathway which targets misfolded proteins of the endoplasmic reticulum for ubiquitination and subsequent degradation by a protein-degrading complex, called the proteasome.
• The recognition of misfolded or mutated proteins depends on the detection of substructures within proteins such as exposed hydrophobic regions, unpaired cysteine residues and immature glycans.
• In mammalian cells for example, there exists a mechanism called glycan processing. In this mechanism, the lectin-type chaperones calnexin/calreticulin (CNX/CRT) provide immature glycoproteins the opportunity to reach their native conformation. They can do this by way of reglucosylating these glycoproteins by an enzyme called UDP-glucose-glycoprotein glucosyltransferase.

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• translocon (commonly known as a translocator or translocation channel) is the complex of proteins associated with the translocation of nascent polypeptides across membranes.
• eukaryotes the polypeptides are transported into the interior (cisternal or luminal) space of the endoplasmic reticulum (ER) from the cytoso
• process requires the protein to cross a hydrophobic lipid bilayer.
• Translocators can also move polypeptides (such as damaged proteins targeted for proteasomes) from the cisternal space of the endoplasmic reticulum to the cytosol. This requires the expenditure of energy in the form of GTP

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• fatty acid is a carboxylic acid with a long aliphatic tail (chain), which is either saturated or unsaturated.
• Fatty acids are important sources of fuel because, metabolized, they yield large quantities of ATP
• The brain cannot use fatty acids as a source of fuel; it relies on glucose or ketone bodies

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• Acetyl coenzyme A or acetyl-CoA is an important molecule in metabolism, used in many biochemical reactions.
• convey the carbon atoms within the acetyl group to the citric acid cycle (Krebs cycle) to be oxidized for energy production.
• acetyl-CoA is the thioester between coenzyme A (a thiol) and acetic acid (an acyl group carrier
• produced during the second step of aerobic cellular respiration, pyruvate decarboxylation, which occurs in the matrix of the mitochondria

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• (PAKs) are members of a family of enzymes.^[1] They serve as targets for the small GTP binding proteins CDC42 and Rac and have been implicated in a wide range of biological activities.

   

  Members include:

   
   
  • PAK1, regulating cell motility and morphology^[2]
   
  • PAK2, possibly playing a role in apoptosis^[3]
   
  • PAK3, possibly for dendritic development and for the rapid cytoskeletal reorganization in dendritic spines associated with synaptic plasticity^[4]
   
  • PAK4, a mediator of filopodia formation^[5]