M/S BIOLOGY Flashcards
for each tissue, understand the embryology, development, biochemistry and metabolism, structure, function, and classification. 1. Connective tissue cells and components: fibroblasts, collagens, proteoglycans, elastin, matrix glycoproteins 2. Joints and ligaments: diarthrodial joints, intervertebral discs, synovium, cartilage 3. Bone: development, structure, cellular basis of turnover and remodeling, hormonal and cytokine regulation 4. Muscle and tendons 5. Blood vessels (45 cards)
What does CD44 hyaluronic acid binding protein bind, and what role does it play?
cd44 is a cell surface glycoprotein (ch 1, cd44 gene), expressed on many cell types, that is a receptor for hyaluronic acid as well a collagen, MMPs, and osteopontin. Many post translational modifications alter function. Plays a role in lymphocyte maturation in thymus, splice variants occur in neoplastic markers.
What is the immediate target of Wnt protein and what pathways are stimulated?
Wnt protein (Wingless-related integration site) binds to the Frizzeled family receptor which passes the signal to the protein Disheveled inside the cell. The canonical pathway then regulates gene expression, the noncanonical planar cell pathway deals with cytoskeleton and noncanonical calcium/Wnt deals with calcium inside the cell.
What is tensin, and what does it link?
Tensin is a 220 kda multi-domain protein that links integrin heterodimers to the plasma membrane, binds to actin filaments, and contains a phosphotyrosine binding protein at the C terminus and a protein tyrosine phosphatase at the N terminus. It is an important component linking the cellular membrane, actin cytoskeleton, and signal transduction.
What is selenoprotein N1?
Selenoprotein contains selenocysteine, and N1 mutations cause muscular dystrophy and in knockout mice results in delayed vertebral fusion.
What is nebulin?
Nebulin is an actin binding protein (600 – 900 kDa) that may act as a ruler for actin length. It also inhibits ATPase activity in a calcium-calmodulin sensitive manner. It’s mutated form results in nemaline myopathy.
What is dynamin?
Dynamin is a 96 kDa GTPase responsible for endocytosis, pinching off the vesicle neck.
What is insulin receptor substrate 1?
Insulin receptor substrate 1 (IRS1) binds to the insulin receptor SH domain, gets phosphorylated, then transmit signals from insulin and insulin like growth factor (IGF-1) to intracellular pathways PI3K/Akt, Erk and MAP kinase. Insulin receptor substrate 1 (IRS-1) contains a single PH Domain and PTB (phosphor tyrosine binding) domain. Deficiency results in mild diabetes but marked growth impairment.
How many types of collagen are there?
There are over 28 types of collagen formed from various combinations of 34 collagen genes. Over 1000 different mutations so far known to cause phenotypic changes.
Common types are I through V, I skin, tendon and bone, II cartilage, III reticulate, IV basement membrane, V cell surface-hair and placenta.
How many genes participate in metabolic pathways leading to type 1 diabetes, rheumatoid arthritis, and Crohn’s disease?
There are at least 149 genes in diabetes type I, 189 in rheumatoid arthritis, and 277 in Crohn’s disease that participate in functional pathways that predict disease susceptibility. Use genotypic data from the Welcome Trust case control Consortium on 14,000 Caucasian UK patients and 3000 controls with 7 diseases; Crohn’s, rheumatoid arthritis, type I diabetes, hypertension, type II diabetes, bipolar disorder. Looked at 1415 genes, finding 20,309 snips within 10 KB of the genes.
What is a reticular cell?
A reticular cell is a type of fibroblast that synthesizes type III collagen producing reticular fibers. These fibers are surrounded by cytoplasm. Reticular cells are found in the spleen, lymph nodes, and may direct B and T cells within the lymphatic tissue.
What is matrix Gla protein?
Matrix Gla protein (MGP) is present usually with osteocalcin in bone, and shares the ability to need vitamin K2 to form its Ca++ binding gamma carboxylic acid structure, and increase production with vitamin D
What gene produces osteocalcin and accounts for what sort of metabolic changes?
(gene) BGLAP (Gamma-carboxyglutamic acid protein, bone) codes for osteocalcin (100 aa, 11Kda), one of six splice variants of pre-Pro osteocalcin. Osteocalcin is secreted solely by osteoblasts and makes up 2% of bone, binds strongly to calcium and apatite. it acts as a hormone causing insulin production, directing fat cells to induce adiponectin, and increases sensitivity to insulin. It may enhance synthesis of testosterone.
What protein inhibits Wnt signaling?
WIF1 (Wnt inhibitory factor 1) binds Wnt protein with an inhibitory domain. It also has 5 EGF like domains, and is present in all vertebrates. WIF1 may be involved in mesoderm segmentation.
wikipedia 2019
What proteins can bind to thrombospondin 1 (TSP1)?
thrombospondin1 (TSP1) is a multi-domain 180kD protein that can bind fibrinogen, fibronectin, laminin, type V collagen, and integrins.
Thrombospondin has different effects on different cell types which differ by cell membrane receptors-type and density. Macrophages may end up secreting TNF alpha, IL-6 and IL 12 whereas endothelial cells may undergo apoptosis.
What cell adhesion receptors can interact with thrombospondin 1 (TSP1)?
thrombospondin1 (TSP1) is a multi-domain 180kD protein that can interact with CD36, CD47, integrins, and syndecan.
cd36 - integral membrane protein, aka platelet glycoprotien 4, Fatty acid translocase, scavenger receptor class B.
CD47 - aka IAP integrin associated protein. Transmembrane protein of immunoglobulin class.
syndecan - coreceptor for G protein-coupled receptors.
What is the structure of BMP1?
Bone morphogenic protein 1 contains 202 residues, 10 helices, 11 strands in beta sheets, and ligans for an acetyl group and zinc ion. It is a metalloproteinase rather than a member of the TGFbeta superfamily. BMP1 may play a role in bone and cartilage development as procollagin peptidase.
BMP2 through 7 belong to the TGFbeta protein family
wikipedia 2019
How do BMPs work?
BMPs other than BMP1 are TGFbeta family proteins released by osteoprogenitors and mesenchymal cells, osteoblasts, bone extracellular matrix, and chondrocytes. They target mesenchymal, osteoprogenitor cells, and osteoblasts to develop into chondrocytes, and osteoblasts. BMP receptors may phosphorylate each other then cooperate to produce SMADs of many types which go on to coordinate gene expression.
BMP1 is a metalloproteinase.
What mutations cause hereditary hemorrhagic telangiectasia?
Hereditary hemorrhagic telangiectasia (HHT) may be due to over 600 mutations. Endoglin, activin receptor like kinase 1 (ALK-1) , Smad4 (MADH4), are commonly involved. Most mutations involve TGF-beta superfamily signaling with defective endothelial cell function.
wikipedia 2019
How is a collagen fibril formed?
left-handed alpha helical alpha chains are formed in the rough endoplasmic reticulum where the N-terminal signal peptide is cleaved, proline and lysine residues are hydroxylated and glycosylated. The right-handed triple helix (procollagen) is formed from the propeptide chains, shipped to the golgi apparatus and secreted as procollagen. Collagen peptidases trim the procollagen into tropocollagen. Lysyl oxidase then links lysine and hydroxylysine to form aldehyde groups which eventually undergo covalent bonding into a polymer of tropocollagen known as a collagen fibril.
What inherited diseases are caused by abnormalities in collagen fiber formation-changing procollagen into tropocollagen?
Ehlers-Danlos syndrome is caused by defects among collagen peptidases changing procollagen into tropocollagen
Endoglin is part of what receptor complex and contains what kind of active motifs.
Endoglin is a type I membrane glycoprotein (CD 105, END, HTT1), 668 residues 180 kDa, part of the TGF-beta receptor complex is important in regulating tumor growth and metastases. The extracellular portion binds ligands such as BMP9, and has an RGD (arginine-glycine-aspartic acid) domain for integrin adhesion. The intracellular portion has a PDZ binding motif which helps binding to cytoskeletal membranes.
What superfamily do activin and inhibin belong?
Activin and inhibin are dimeric proteins of the TGFbeta superfamily that were discovered in 1986 to use TGF-beta receptors to modify FSH secretion. Multiple other effects were discovered later.
By what mechanism does nodal regulate mesoderm formation?
Nodal(nodal growth differention factor) is a member of the TGFbeta superfamily of cytokines, 347aa, which regulates mesoderm formation in a species-specific manner producing right left symmetry.
What is the beta-catenin cytoplasmic destruction complex, and what does it do?
The beta-catenin cytoplasmic destruction complex marks beta-catenin for ubiquination by using GSK-3 to phosphorylate it using actin as a scaffold, This pathway augments the ubiquination necessary for proteosome destruction. This process makes Wnt signalling dependent on beta-catenin generation.
APC has multiple binding sites for beta-catenin, and SAMP motifs result in binding Axin proteins through their terminal RGS domains. The C-terminal DIX domains of axin stick to each other forming a large complex. GSK-3 binds to the midportion of axin and phosphorylates beta catenin also on axin thus marking it for proteosomal destruction.
APC - Adenomatous Polyposis Coli protein
DIX - DIsheveled aXin domain, binds axin to disheveled
GSK-3 - Glycogen Synthetase Kinase 3
RGS - Regulator of G protein Signaling) domains
SAMP - ser-ala-met-pro
wikipedia Beta catenin 2019
