Week 1 Flashcards
(107 cards)
The most common type of genetic variation among humans is ___ and they can help predict a persons risk of a particular disease or their response to certain medications
There is also ___, which are different numbers of large contiguous stretches of DNA, but less is known
^**These are important for determining the function of genes and the elements that regulate them throughout the genome in order to serve as markers for disease risk for multigenic complex disease
SNPs (Single-nucleotide-polymorphisms)
CNVs (Copy-number-variations)
____ are tightly packed and transcriptionally inactive forms of chromatin and ___ are loosely packed and transcriptionally active forms of chromatin
** DNA is wound around an octomeric histone core, and this core (which consists of 8 histones each) makes up. Single nucleosome… The nucleosomes are connected to each other via DNA linkers and H1 linker histones, and these linked nucleosomes are what make up chromatin (if it is tightly packed = heterochromatin, and if it is loosely packed = euchromatin)… These chromatin then make up the chromosome
Heterochromatin, Euchromatin
Proteins act as enzymes, structural components, and signaling molecules but only make up 1.5% of the genome
The other 98.5% of the non-protein coding sequences include
1) Promoter and Enhancer regions that provide the binding site for ____
^** Promoters initiate gene transcription and enhancers are regulatory elements that can modulate gene expression over distances
2) Binding sites for factors that organize and maintain higher order chromatin structures
3) Can regulated gene expression even though they aren’t translated into proteins and include ___ and ____
4) Jumping genes that are implicated in gene regulation and chromatin organization called ___
5) Chromosome ends called ___ and chromosome tethers called centromeres that are special structural regions
Most genetic variation is associated with these non-protein-coding regions of the genome, and it’s called ____
1) TFs
3) Micro-RNAs and Long Noncoding RNAs
4) Mobile genetic elements (aka transposons)
5) Telomeres
Polymorphisms
Heritable changes in gene expression (aka in a chromosome) that is not caused by alterations in DNA sequencing is called ___
The relative state of DNA unwinding, to make them active or inactive, is done via histone modification
Histones can be methylated (lysine and arginine), acetylated (lysine), or phosphorylated (serine) and DNA can be ____, which normally leads to transcriptional ____ (activation or inactivation?)
^** However, note that these modifications are reversible
Histone ___ tends to open up and activate transcription (Via HATs) vs Histone ____ tends to condense and inactivate transcription
^ HDACs deacetylase and therefore lead to inactivation.
**^ MicroRNA is both epigenetically regulated (most), but could also be classified as a polymorphism
Epigenetics
Methylated, inactivation
Acetylation, Methylation
Micro RNA (miRNA) are transcribed but not translated and once cleaved by ___ and then compelxed with ___, the miRNA perform ___transcriptional ____ of the mRNA gene expression in order to breakdown the mRNA and block its translation (aka gene silence)
If the RISC complex matches the target mRNA perfectly, it ___ the mRNA and if it is an imperfect match, it ____ the mRNAs ability for translation… Both lead to gene silencing
^*LncRNA (Long Noncoding RNA is another noncoding regulatory RNA that can silence or increase transcription etc.)
DICER, RISC, Posttranscriptional silencing
Cleaves, represses
___ is normally restricted to the inner face (cytoplasm face) and contains a ____ charge, but if it flips to the extracellular face (which occurs during apoptosis) it becomes an “eat me” signal for phagocytes
Phosphatidylserine, negative
Name if it is expressed out the extracellular surface (outer leaflet) or cytoplasmic surface (Inner leaflet) or both for the cell membrane
1) Phosphatidylcholine
2) Phosphatidylethanolamine
3) Phosphatidylserine
4) Sphingomyelin
5) Gylcolipids
6) Cholesterol
7) Phsophatidylinositol
1) Outer
2) Inner
3) Inner
4) Outer
5) Outer
6) Both
7) Both
Remember, small/nonpolar/hydrophobic molecules can cross the lipid membrane via passive diffusion
If the molecules are hydrophilic, larger than 75 KDs, or charged then they must use ____ proteins that create a hydrophilic pore to cross the membrane or ___ proteins that bind the solute and change conformation to cross the membrane
Certain small molecules, like vitamins/GPI molecules/CAMP proteins/SRC kinases/Folate receptors, can be taken up in ___ via endocytosis (also called potocytosis aka cellular sipping), which are non-coated plasma membrane invaginations associated with taking up extracellular fluid, membrane proteins, some receptors, etc.
Two other forms of endocytosis are pinocytosis (aka cell drinking) or receptor mediated endocytosis (surface receptor ligand pairs) and both of these involve ___-coated pits and vesicles
LDLs are taken up via ____
Channel, Carrier
Caveolae
Clathrin
Receptor mediated endocytosis
There are three major classes of cytoskeletal proteins
1) ___ microfilaments, which form from the ___ protein G-actin and these G-actin momoners noncovalently polymerize into long ___ called F-actin that intertwine to form double-stranded helices with a defined polarity
^** One example of the F-actin is myosin in muscle cells
2) _____ filaments have characteristic tissue-specific patterns of expression that can be useful for assigning a cell of origin for poorly differentiated tumors (ex: Vimentin, Desmin, Neurofilaments, Cytokeratins, etc)
^** Found mainly in a polymerized form within cells and impart tensile strength and allow the cells to bear mechanical stress
3) ___ that act as connecting cables for “molecular motor” proteins that use ATP to move vesicles, organelles, or other molecules around cells along microtubules
1) Actin, Globular, Fillaments
2) Intermediate
3) Microtubules
____ filaments are important for tensile strength and allows the cells to bear mechanical stress
^** They also form the major structural proteins of the skin and hair
___ A, B, and C are important for maintaining nuclear morphology and regulating normal nuclear transcription
___ is found in mesenchymal cell like fibroblasts or endothelium
___ is found in muscle cells, forming the scaffold on which actin and mysoin contract
Neurofilaments are found in axons of neurons for strength and rigidity
Glial fibrillary acidic proteins are found in glial cells and around neurons
Cytokeratins are found in many cells and can be used as cell markers
Intermediate
Lamin
Vimentin
Desmin
Cell-cell interactions occur via junctions to provide mechanical links and enable surface receptors to recognize ligands on other cells and are organized into 3 basic types
1) ____ seal adjacent cells together to create a continuous barrier that restricts the paracellular (between cells) movement of ions and other molecules. They also segregate the apical vs basolateral domain to maintain cell polarity
2) ___s mechanically attach cells and their intracellular cytoskeletons to other cells or to the extracellular matrix (ECM)
^ Cell-ECM = Hemidesmosome, Cell-Cell broad band = Belt desmosome, Cell-Cell small and rivet like = Spot desmosome
3) ___s mediate the passage of chemical or electrical signals from one cell to another (like in cardiac myocytes) aka signaling is between adjacent cells via hydrophilic connexons that permit the movement of small ions (like calcium), various metabolites, and potential second messengers like cAMP, but not large macromolecules
1) Tight junctions (aka occluding junctions)
2) Desmosomes (Anchoring junctions)
3) Gap junctions (Communicating junctions)
Cell-Cell desmosomal junctions are formed by homo-typic association of transmembrane glycoproteins called ____ and for ___-desmosomes the transmembrane adhesion molecule is called E-cadherin, which is associated with intracellular actin microfilaments that can influence cell shape/motility
In hemidesmisomes, the transmembrane connector proteins are called ___ and these also attach to intracellular intermediate filaments to functionally link the cytoskeleton to the ECM
Cadherin, Belt
Integrins
New proteins destined for the plasma membrane or beyond, are synthesized in the ___ via membrane-bound ribosomes on the cytosolic face of the RER (to translate the mRNA into proteins) and assembled in the ___
^** Cis Golgi recycles proteins back to the ER and Trans golgi sorts proteins and lipids and dispatches them to other organelles or secretory vesicles destined for extracellular release
**Proteins intended for the cytosol are synthesized on free ribosomes
___ molecules retain proteins in the ER until the modifications (like protein folding or disulfide bonds forming or oligosaccharides attached) are complete and proper conformation is achieved. If this fails, the protein is retained and degraded in the ER
^** If to many misfolded proteins accumulate, the ER stress response occurs (also called UPR- Unfolded protein resposne) that triggers cell death
** The SER isn’t very important except for synthesizing steroids, catabolizing lipid soluble molecules, and sequestering intracellular calcium
RER, Golgi
Chaperone
____ are intracellular organelles that contain degradative enzymes (acid hydrolases) that permit the digestion of a wide range of macromolecules
^**Fuse with endosomes and phagosomes
____s are specialized cell that selectively chews up denatured proteins, releasing peptides
Proteasomes degrade ___ proteins via tagging them with ____ molecules
Lysosomes
Proteasomes
Cytosolic, ubiquitin
*** Pinocytosis or receptor mediated endocytosis leads to the internalization of contents inside a vesicle, and the vesicle matures and acidifies, which is called an ___ (Early endosome -> Late endosome -> EndoLysosome)
Macrophages or neutrophils can take microbes into a cell via ____ and once internalized is called a phagosome (Phagosome -> Phagolysosome)
Both of these vesicles (endosome or phagosome) can meet with a lysosome in a process called ____ to facilitate the degradation of the internalized contents*
___ is the endcytotic transport of solute and/or bound ligand from one face of a cell to another
Endosome
Phagocytosis
Heterophagy
Transcytosis
Senescent organelles and large denatured protein complexes are shuttled into lysosome in a process called ___ (Senescent organs or Denatured proteins -> Initiation complex and nucleation complex promotes the nucleation of the autophagosomal membrane -> Elongation and closure of the autophagosomal membrane via the microtubule-associated protein light chain 3 aka ___ -> Mature Autophagosome -> Fusion with endosome that turns into a lysosome aka an autophagolysosome -> Degradation via lysosomal enzymes)
^** Autophagy is an adaptive response, triggered by nutrient depletion (to preserve cell viability by allowing the cell to cannibalize itself to survive) or certain intracellular infections (aka host defense against certain microbes)
Autophagy
LC3 **(Useful as a marker for cells undergoing Autophagy)
If there is an external cellular injury (toxic, ischemia, or trauma), mitochondria can be damaged and this leads to the insertion of ____ pores that allow the dissipation of the ___ potential so that ATP can’t be produced and the cell dies in a process called ____
Discussed later, but if mitochondria are damaged via intrinsic pathways (DNA damage or Intracellular stress) or also extrinsic pathways (Cytotoxic T cells or Inflammatory Cytokines) the mitochondria become leaky and ___ leaks into the cytosol of the cell, where it forms a complex with other prtoeins that eventually induce ____
^** Failure of programmed cell death = malignancy and Premature cell death = Neurodegenerative disease
Membrane permeability transition pores (in the outer membrane), Proton, Necrosis
Cytochrome C, Apoptosis
Vitamin D and steroid hormones bind to ___ receptors that are transcription factors that are activated by lipid-soluble ligands that can easily cross the plasma membrane
Transmembrane proteins with extracellular domains that bind soluble secreted ligands are called ___ receptors
Intracellular
Cell-surface
Cellular receptors are grouped into several types based on the signaling mechanisms they use and the intracellular biochemical pathways they activate
1) ___s are integral membrane proteins that cross-link once a ligand binds and activates intrinsic tyrosine kinase domains located in their cytoplasmic tail (Insluin, Epidermal growth factor, PDGF)
2) ___ have no intrinsic catalytic activity and instead phosphorylate specific motifs on the receptor or other proteins (Rous Sarcoma Virus - SRC and include SH2 and SH3 domains)
3) ____s are 7-transmembrane domain that causes cAMP or IP3 downstream to be activated (pharmacologic targets)
4) ___ receptors bind lipid soluble ligands and the complex can bind directly to nuclear DNA (Breast cancer)
5) ____ recognizes a ligand on a distinct cell and then gets cleaved, and the intracellular fragment enters the nucleus and forms a transcription complex
6) Wnt protein ligands can influence cell development via a pathway involving Frizzled, which when activated releases intracellular ___ that then migrates to the nucleus and acts as a TF
^** Lrp5 and 6 act as coreceptors for the WNT/Frizzled pathway ((LDL receptor related proteins)
1) Receptor tyrosine kinases
2) Non-RTKs
3) G-proteins
4) Nuclear
5) Notch
6) B-Catenin
For RTKs, a ligand binds to the receptor -> Dimerization and auto-phosphorylation of the tyrosine residues -> Bridging protein attatches RTK to inactive ___ with GDP bound -> GDP is then dissociated and GTP binds to activate the RAS -> RAF -> MAPK -> Activates gene transcription -> Cell cycle progression
^** RAS can also activate -> PI3K -> Akt -> mTOR -> Gene transcription
** Also note if a mutation in the ability for RAS to hydrolyze GTP occurs, then it won’t become inacrtive and proliferative signaling can occur
RAS
*** COME BACK TO THIS ONCE CHAPTERS 1-3 ARE COMPLETE
Name the growth factor * THIS IS A LOT, MAYBE THE NEXT CARD WOULD BE MORE USEFUL
1) Comes from activated macrophages, salivary glands, kertinocytes, etc and is mitogenic for keratinocytes and fibroblasts (also stimulates keratinocyte migration and formation of granulation tissue)
2) Comes from activated macrophages, keratinocytes, etc and stimulates the proliferation of hepatocytes (liver cells) and other epithelial cells
3) Comes from fibroblasts, stromal cells in the liver, and endothelial cells and enhances proliferation of hepatocytes and increases cell motility
4) Comes from mesenchymal cells and stimulates the proliferation of endothelial cells (lines interior surface of blood vessels and lymphatic vessels) and increases vascular permeability
5) Comes from platelets, macrophages, endothelial cells, smooth muscle cells, and keratinocytes and is chemotactic (movement in response to a chemical stimulus) for neutrophils, macrophages, fibroblasts, and smooth muscle cells; along with activates and stimulates proliferation of fibroblasts and endothelial cells; and finally it stimulates ECM protein synthesis
6) Comes from macrophages, mast cells, endothelial cells, etc and is chemotactic and mitogenic for fibroblasts and stimulates angiogenesis and ECM protein synthesis
7) Comes from fibroblasts and stimulates keratinocyte migration, proliferation, and differentiation
8) Comes from platelets, T lymphocytes, macrophages, endothelial cells, keratinocytes, smooth muscle cells, and fibroblasts and is chemotactic for leukocytes and fibroblasts and stimulates ECM protein synthesis and suppresses acute inflammation
1) EGF (Epidermal growth factor)
2) TGF-Alpha (Transforming growth factor-alpha)
3) HGF (Hepatocyte growth factor)
4) VEGF (Vascular endothelial growth factor)
5) PDGF (Platelet-derived growth factor)
6) FGF (Fibroblast growth factor)
7) KGF (Keratinocyte growth factor)
8) TGF-Beta
1) Mutations or amplifications can occur in lung, head, neck, breast, and brain cancers
2) MET is the receptor and over expressed in kidney and thyroid cancer
3) Induces blood vessel development after injury and tumors
4) Recruits cells to sites of tissue injury and inflammation
5) Can lead to acrhondroplasia and malignancies
6) Drives scar formation and applies the breaks on inflammation that accompanies wound healing “pleiotripic with a vengeance”
1) EGF (Epidermal growth factor)
2) HGF (Hepatocyte growth factor)
3) VEGF (Vascular endothelial growth factor)
4) PDGF (Platelet-derived growth factor)
5) FGF (Fibroblast growth factor)
6) TGF-Beta
The Extracellular Matrix has various functions including
1) Mechanical support
2) **Controlling cell proliferation (along with locomotion and/or differentiation) via binding and displaying ___ to their receptors, which can then activate cytoplasmic signal transduction pathways to the nucleus and mediate cell signaling
Or cellular receptors of the ___ family that can interact with the cytoskeleton at ___ complexes to directly transduce signals in the nucleus (cytoskeleton-mediated signals) or these Integrins can also produce intracellular messengers that act on the nucleus as well **
3) Scaffolding for tissue renewal due to the ____ and this also helps establish tissue micro-environments via acting as a boundary between the epithelium and underlying connective tissue for both support and function
2) Growth factors
Focal adhesion, Integrin
3) Basement membrane
For components of the ECM, the interstitial matrix is synthesized via ___
^** It includes Collagens, Elastin, Proteoglycans, and Hyaluronans
The ____ is synthesized by contributions from the overlying epithelium and underlying mesenchymal cells
^** It includes Type 4 Collagen, Laminin, and proteoglycans
Mesenchymal cells (aka Fibroblasts)
Basement Membrane