Cytoskeleton, Stem Cells, Nucleus, Cell Division, & Cancer

Flashcards to help review lecture notes on Cytoskeleton, Stem Cells, Nucleus, Cell Division, & Cancer

Is the cytoskeleton dynamic or static?

Dynamic

What is the size of Actin (F-actin)?

7-9 nm

What is needed for F-Actin Polymer formation?

ATP and magnesium

What happens at the + end of polarized F-actin?

G-actin monomers are added to grow F-actin

What happens at the - end of polarized F-actin?

G-actin monomers fall off F-actin

What is the function of Cofilin?

Severing protein that binds to (-) end and severs G-actin

What is the function of Formin?

Nucleating protein

What is the function of Profilin?

ATP/ADP exchanger

What is the function of Thymosin B-4?

Regulates F-actin growth and prevents G-actin binding

What is the function of S1 Myosin Head?

Helps contract muscles

What is the function of Alpha actin?

Contractile structure (Cytokinesis)

What is the function of Beta Actin?

Aid in cell movement

What is the function of Gamma actin?

Stress fibers

What is Treadmilling?

G-actin adding at (+) end at same rate as actin falling off at (-) end

What is the function of Cytochalasin D?

Inhibits polymerization

What is the function of Phalloidin?

Promote polymerization

What is Listeria?

Food poisoning bacteria that can infect unborn child

What causes deafness in Daphnamus gene?

Defect in formin causes deafness

What is the effect of rapamycin treatment in fruit flies with less F-actin?

Healthier/live longer

What is the size of Intermediate filaments?

10 nm

What is the relationship between stretching and force in Intermediate filaments?

More force = more stretchy

Where can Keratin be found?

Skin, hair, nails, etc.

Where can neural filaments be found?

Axons

What are Lamins?

Skeleton of nucleus

What causes Epidermolysis bullosa simplex (EB)?

Defective keratin filaments

What does VYJUVEK do?

Fixes the genes for anchoring fibrils

What is the size of Microtubules?

25 nm

How many rings are in ProtoFilaments?

13 rings

What are Microtubules made of?

Alpha tubulin & Beta tubulin Dimers

What does Alpha tubulin have?

Non-exchangeable GTP

What does Beta tubulin have?

Exchangeable GTP for GDP

What does rescue mean in relation to microtubules?

Assemble/polymerize

What does catastrophe mean in relation to microtubules?

Disassemble/depolymerize

What is Tau?

Microtuble stabilizing protein in axon

What happens when Tao is defective?

Breakdown Microtubles → Axon shrink → Alzeimers

What does Colchicine do?

Depolymerizes microtubules

What does Taxol/Taxotere do?

Promotes microtuble Polymerization

What is Molecular Motors?

Help move vesicles or organelles along microtubules

What direction does Kinesin travel?

Anterograde away from cell / nucleus

What is the function of Kinesin-5?

Can pull on adjacent microtubules

What is the function of Kinesin-13?

No motor activity - hydrolyze ATP

What direction does Dynein travel?

Retrograde towards cell / nucleus

What happens in Kartagener’s Syndrome?

Dynin arms fail, Mucus build up

What are Stem cells?

Cells that differentiate

What is Differentiation?

Cell specialization

What is Totipotent?

Cell is not restricted; - can become any type of cell

What is Pluripotent?

More restricted than totipotent

What is Multipotent?

More restricted than pluripotent

What is Unipotent?

Cell can only turn into 1 type of cell

What is Transdifferentiation?

Inducing cell differentiation without going back to embryonic stage

What is Dedifferentiation/Redifferentiation?

Inducing cell differentiation with going through embryonic step

What is Stem cell niche?

Molecules/cells that surround stem cells

What is Fusogenic?

Stem cells like to fuse together

What is Biodistribution and Homing?

Ability of stem cell to find where it needs to go (home)

What is STAP?

Acid shock to induce pluripotency

What are iPSC (induced pluripotent stem cells)?

Made by Shinya Yamanaka using reprogramming factors

Where do hESCs (human embryonic stem cells) come from?

From inner cell mass of blastocyst

What is Chimera test?

Only true test of totipotency

What are Adult human stem cells?

Adipose-derived mesenchymal Stem cells

Where do Fetal Stem cells come from?

From amniotic fluid, placenta, and umbilical cord

What is the process of Therapeutic cloning?

SCNT (somatic cell nuclear transfer)

What is the process of Reproductive cloning?

SCNT (somatic cell nuclear transfer)

What are SCID mice (Severe Combined ImmunoDeficiency)?

Mice that don’t have B and T cells (no immune system)

Who are some notable people in SCNT?

John Guordon - 1st person to clone tadpole, Sir Ian Wilmut - Cloned Dolly sheep

What is Parthenogenesis?

Generation of animal without sperm/fertilization (asexual reproduction)

What is Tumorigenicity?

Stem cells can cause tumors

What is Immunogenicity?

Stem cells can cause immune responses when injected into patients

What is Inappropriate Differentiation?

Stem cells can differentiate into wrong cells

What is Cord blood?

Umbilical cord blood cells are stored for blood stem cell therapy when needed

What is Hematopoiesis?

Ability of cells to differentiate into different types of blood cells

What is C. Elegans?

Model organisms used for research

Who worked with C. Elegans to find apoptotic genes?

Robert Horvitz

What does anucleate mean?

Not all cells have nuclei

Why don't RBCs have nuclei?

Have odd shape to promote CO2/O2 exchange

Why don't Epidermic have nuclei?

Lose nucleus and cytoplasm as they differentiate to form skin barrier

Why don't Lens of the eye have nuclei?

Lens fibers (middle layer) are anucleated to create a transparent and optically clear eye

What are the Pores in the nucleus?

Site of protein/mRNA exchange

What are the functions of Nucleoplasmin?

Genome stability, Nucleosome assembly, Transcriptional regulation

What are Lamins in relation to the nucleus?

Kargoskeleton - skeleton for nucleus (provide structure)

What 3 key lamins comprise nuclear lamina?

Lamins A,B, and C

Where does nuclear dissolution happen?

Converts chromatin at the nuclear envelope

What happens when Lamin B is phosphorylated during mitosis by MPF?

Causes nuclear dissolution & DNA condenses

What is Hutchinson-Gilford Progeria?

Disease that causes fast aging caused by lamin A gene mutation

What is Lonafarnib?

Prevent addition of Farneysl groups on Lamin A

Who discovered Cell Cycle?

Howard + Pele studied Broad Bean to discover Cell Cycle

What causes Cancer?

Loss of cell cycle control

Who are Howard + Pele?

Suggested cell cycle in 1953

What is G0 phase?

Quiescent (resting) period - differentiated cell (Do not divide)

Who is Arthur Pardee?

Investigated with 3T3 Cells - Mice fibroblasts

What growth factors are needed to get through G1 phase → S phase?

PDGF, EGF, and Insulin

What is the Checkpoint (Between G1 and S) a Restriction Point?

Checks fidelity (accuruacy of DNA) of cell cycles

What happens if you PASS at restriction point?

Commitment to cell cycle

What happens in G2?

Cell verifies that DNA has been replicated and there are no errors

Where do new nuclear envelopes originate?

New nuclear envelopes originate from ER

What is MPF?

Cyclin B + CDK1

What is Cell synchrony?

Methods used - allows synchronization of different cells through cell cycle

What does Amino acid deprivation do to the cell cycle?

Stalls cell cycle in G1

What does Fetal calf Serum deprivation do to the cell cycle?

Stalls in G1

What does Protein synthesis inhibitor do to the cell cycle?

Stalls in G1

What does Microtubule inhibitors do to the cell cycle?

Stalls in M