Cell and Molecular Biology: Exam 4

Signal Transduction

In cell biology, a series of molecular changes that converts a signal on a target cell's surface to a specific response inside the cell

Second Messangers

substances that trigger communication after the actions of neurotransmitters at their receptors have been completed. Second messengers are intracellular signaling molecules released by the cell to trigger physiological changes such as proliferation, differentiation, migration, survival, and apoptosis. (small, polar and mobile)

IP3

A second messenger that functions as an intermediate between certain nonsteroid hormones and a third messenger, a rise in cytoplasmic Ca2+ concentration.

CaH

calcium channel

cAMP

Cyclic adenosine monophosphate (cAMP, cyclic AMP or 3'-5'-cyclic adenosine monophosphate) is a second messenger important in many biological processes. cAMP is derived from adenosine triphosphate (ATP) and used for intracellular signal transduction in many different organisms, conveying the cAMP-dependent pathway.

cGMP

Cyclic guanosine monophosphate (cGMP) is a cyclic nucleotide derived from guanosine triphosphate (GTP). cGMP acts as a second messenger much like cyclic AMP. Its most likely mechanism of action is activation of intracellular protein kinases in response to the binding of membrane-impermeable peptide hormones to the external cell surface

PDE

Phosphodiesterase; A phosphodiesterase (PDE) is any enzyme that breaks a phosphodiester bond.

PLC

Phospholypase C; a class of enzymes that cleave phospholipids before the phosphate group

DAG

Diacyl Glycerol

PIP2

Phospholipid; Phospholipids are a class of lipids that are a major component of all cell membranes as they can form lipid bilayers

PKC

Protein Kinase

Synaptic Vesicle

Saclike structures found inside the synaptic knob containing chemicals usually neurotransmitters

v-snare

a protein incorporated into a vesicle membrane during vesicle formation that is recognized by a t-snare in a target membrane

t-snare

a protein in a target membrane that recognizes a v-snare in a membrane vesicle

synaptotagmin

Calcium-sensing SNARE that aids in fusion when calcium enters the cell

syntaxin

plasma membrane protein; mobilization; interacts with synaptotagmin to pull vesicle and plasma membrane close together; can anchor voltage gated Ca++ channels

botulinum toxin

An acetylcholine antagonist; prevents release of ACh by terminal buttons. This toxin cuts synaptotagmin from the synaptic vesicle, therefore does not allow vesicle to fuse with synapse membrane and release the neurotransmitter.

PDGF

Platelet derived growth factor; Stimulates proliferation of smooth muscle, fibroblasts and endothelial cells. Gets its own tubing going.

GEF

Gaunisine exchange factor; once GEF is activated catalyzes conversion of GDP to GTP, which then activates RAS

Ras

...

Raf

Map Kinase Kinase Kinase

Mek

Map Kinase Kinase; a kinase whose job it is to phosphorylate map kinase

Erk

Map Kinase; mitogen activated protein

m-cyclin

when it bonds to CdK, it triggers mitosis.

G2 Checkpoint

before mitosis, checks to see if there are mistakes in DNA (enzymes correct and mistakes) also checks size

Metaphase Checkpoint

is not passed when chromosome kineotchores are not attached to spindle fibers

G1 Checkpoint

checks to see if cell size is adequate; chromosomes replication is successfully completed and checks for DNA errors

m-CDK

triggers the events of early mitosis, including chromosome condensation, assembly of the mitotic spindle, and bipolar attachment of the sister chromatid pairs to microtubules of the spindle.

CDK

Cyclin-dependent kinases. A protein kinase that is active only when attached to a particular cyclin. Activity rises and falls depending on the concentration of the cyclin partner.

tubulin

reorganizes cytoskeleton

lamin

breakdown nuclear envelope

APC

Anaphase Promotion Complex; is an E3 Ubiquitin ligase, that unbiquinates m-cyclin.

Velcade

a cancer drug that blocks proteosome 26s which doesn't allow m-cyclin to be degraded, therefore inhibits cell division.

ATM kinase

activated during the presence of cell damage, activates p53, which activates p21 (CDKI), which inhibits CDK 4/6

p53

This tumor suppressor gene causes cell cycle arrest in G1, providing time for DNA repair. If repair is successful, cells re-enter the cycle. If unsuccessful, apoptosis

MDM2

Ubiquitin ligase; promotes p53 degradation, Keeps p53 levels low to continue cell cycle

p21

CDK inhibitor, Cdk inhibitor protein, transcription of this protein is activated by p53, protein binds to S-Cdk and inactivates it so that the cell cycle arrests in G1 phase

Li Fraumeni Syndrome

inheritable p53 deficiency, greatly increases risk for cancer.

apoptosis

Programmed cell death; cell suicide

caspase

a family of cysteine-dependent, aspartate-specific proteases that are associated with apoptosis in neurodegenerative diseases

procaspase

inactive caspase; caspases are important proteins for process of apoptosis (pro-a portion of the caspase that has to be cleaved before the caspase is active.

cytochrome C

Involved in energy transfer, it is a protein released from mitochondria when cell is stressed.

Apa F1

senses high concentration of cytochrome c in the cytoplasm, then assists in activation of procaspase --> caspase. Part of intrinsic pathway of apoptosis.

Intrinsic Apoptosis

Cell decides itself that it needs to die; usually decides this if the cell has a leaky mitochondrion; cyctochrome C activates APAF-1 which activates caspase 9

apoptosome

assembly in which procaspase 9, an initiator caspase in the intrinsic pathway, is activated

Extrinsic Apoptosis

this pathway is initiated by signaling by molecules like the FAS ligand, which in turn signals a series of events that involve activation of caspases. Caspases 8 and 9 are activating caspases and 3 and 6 are executioners.

FAS receptor

integral membrane protein receptor; bound to Fas ligand (integral membrane protein on killer T-cell) when cell expresses novel antigens (viral infection); receptor-ligand interaction triggers signal transduction cascade involving caspases; activation of receptor signaling pathway triggers cleavage and activation of caspase 8 enzyme--> apoptotic cell death of target cell

FAS ligand

Activates Fas molecules on infected cell surface, induces infected cell apoptosis

stem cell

Cells that divide and remain undifferentiated. Three types are totipotent, pluripotent, and multi-potent.

precursor cell

come after lineage-specific progenitor cells and are first cells morphologically distinguishable about what cell types they'll be

differentiated cells

specialized cells that carry out specific functions; skin cells, muscle cells, blood cells, etc.

somatic stem cells

stem cells obtained from differentiated somatic tissue of an organism; adult stem cells usually only unipotent sometime multi potent

unipotent

Can only become one type of cell

multipotent

Cell with limited potential to develop into many types of differentiated cells

pluripotent

Cells that are capable of developing into most, but not all, of the body's cell types

crypt

Crypts (of Lieberkuhn) are tubular invaginations of the epithelium around the villi, in the intestinal lining

embryonic stem cell

An undifferentiated cell, taken from an embryo that has potential to give rise to various other cell or tissue types

morula

A solid ball of cells that makes up an embryo; in humans, this stage occurs within four days of fertilization. early embryo

trophoblasts

What nourishes the embryo before it implants in endometrium

blastocyst

A fluid-filled sphere formed about 5 days after fertilization of an ovum that is made up of an outer ring of cells and inner cell mass. THis is the structure that implants in the endometrium of the uterus.

inner cell mass

The mass of cells in the blastocyst that ultimately give rise to the embryo and other embryonic structues (the amion, the umbilical vessels, etc.)

ectoderm

One of the three primary (embryonic) germ layers formed during gastrulation. Ectoderm ultimately forms external structures such as the skin, hair, nails, and inner linings of the mouth and anus, as well as the entire nervous system.

mesoderm

One of the three primary (embryonic) germ layers formed during gastrulation. mesoderm gives rise to most of skeleton; muscles; circulatory system; reproductive organs; excretory organs

endoderm

One of the three primary (embryonic) germ layers formed during gastrulation. endoderm forms epithelial linings of the digestive, respiratory, and urogenital systems

nuclear transfer

a process in which the nucleus of one cell is transferred into another cell whose nucleus has been removed; cloning

oocyte

a female gametocyte that develops into an ovum after two meiotic divisions

zygote

Fertilized egg

induced pluripotent stem cell

Any cell, even a highly differentiated cell in the adult body, that has been genetically reprogrammed to mimic the pluripotent behavior of embryonic stem cells

yamanaka factors

transcription factors that can induce pluripotent stem cells

oct 3/4

Tx factors that can re-program cells back to stem cells?

sox 2

transcription factor which has sequences in common with sex-determining region on Y chromosome. Works with oct 3 /4

kif 4

...

lipofection

liposomes are used to inject cells with genetic materials; this is easy because both liposomes and the cell membrane are made of a phospholipid bilayer

bombardment

a method of direct gene therapy

retrovirus

an indirect method of gene therapy; virus integrates DNA with host cell, long lasting but may cause mutations

adenovirus

an indirect method of gene therapy; virus does not inter ate DNA, brief but does not cause mutations

adeno-associated viruses

indirect method of gene therapy; integrates dan of host cell only in known, harmless location on chromosome 19.

endostatin

a broad spectrum angiogenesis inhibitor and may interfere with the proangiogenic action

bFGF

basic fibroblast growth factor; promote growth of ne blood cells

VEGF

vascular endothelial growth factor; growth factor that promotes angiogenesis

angiogenesis

Formation of new blood vessels

HUVEC

human umbilical vein endothelial cells

ADV.mEnd

adenovirus with endostatin gene

ADV Beta-Gal

adenovirus with Beta-Gal used as a control