Lecture 13 Flashcards
Hematopoietin Family
Receptor Features: comprised of 1 to 3 subunits
- Subunit expression used to regulate activity
IL-2 Receptor Subuinits (g-sharing)
- a-subunit
- confers ligand specificity; NO transduction
- bg-subunit
- weak binding/ signal transduction
- abg-subunit
- physiologically active
a-subunit
Expressed in activated T-Cells; expressed in activated B-Cells
b-chain bearing
Low-affinity receptors: NO signal transduction (HSC)
- IL-3, IL-5, GM-CSF
High-affinity receptors: YES signal transduction (Myeloid Precursor)
- B-subunit
Interferon Family
Interferes with viral growth; inhibits proliferation and survival of viruses
Interferon-a (Made by multiple cell types)
- Induces ribonucleases (degrades RNA)
- Inhibits protein synthesis (translation)
- Destroys virally infected cells
Interferon-b (made by activated mac/DC and virus-infected cells)
- Induces ribonucleases
- Inhibits protein synthesis
- Destorys virally-infected cells
Interferon-g (made by NK cells and activated T-Cells)
- Drives TH to TH1 (TC development_
- Activates Macs
Interferon-l
Upregulate anti-viral genes
Protein Kinase R
- Activated by dsRNA
- Phosphorylates eIF2a (phosphorylation elongation)
- Blocks initiation of translation
2’,5’-oligoA Synthetase
- Activated by dsRNA
- Activates latent ribonucleases
- Degrades viral mRNA
Mx Proteins
- Inhibits viral transcription
- Detect nucleocapsid proteins
- Prevents virus assembly
Tumor Necrosis Factor Family
Not mainly about tumor necrosis
1. Regulates development and homeostasis
2. Signaling in a variety of tissues
Tumor Necrosis Factor Family (TNF)
- Can be soluble or membrane-bound
- Receptors assemble into trimers
-homotrimers
TNF-a
Macrophage
1. Pro-inflammatory
2. Anti-tumor (apoptosis)
3. Pro-survival
Lymphotoxin-a
Lymphocytes
1. Immune activation
2. MHC expression
3. Increased adhesion
Lymphotoxin-b
Lymphocyte differentiation
BAFF
B-Cell development and homeostasis
APRIL
B-Cell development and homeostasis
CD40L
T-Cell Surface
1. B-Cell differentiation
FasL (CD95L)
TC Cell
1. Induces apoptosis
Signaling
- TNFs can be soluble or membrane-bound
- TACE can liberate soluble TNFa
Signaling
- TNFa can bind to TNFR1 or TNFR2
Caspases
Apoptosis
Kinases
Cell activation/ proliferation
TNF Binding
Induces receptor trimerization
Receptor Trimer
Alters binding within the cytoplasmic domain
TNF-R1
- Binds both TNF-a and TNF-b
- Has a cytoplasmic death domain
- Binding either promotes apoptosis or survival
HeLa Cells
- Expresses Fas on their plasma membrane
- Treated with FasL
- Cells undergo apoptosis
HeLa Cells (2)
- Nuclear Condensation
- Cell Rounding
- Membrane Blebbing
- packets of cellular material
- Plasma membrane keeps its integrity
FasL-induced Apoptotic Pathway
- FasL binding trimerizes Fas receptors
- Cytoplasmic death domains organize
- Trimerized death domains bind FADD
- DED on FADD binds to pro-capase-8
FasL-induced Apoptotic Pathway (2)
- Pro-caspase-8 clustering cleaves/ activates capase-8
- Caspase-8 initates the apoptotic cascade
Interleukin-17 Family
- Functions primarily as homodimers
- Associated with innate/inflammatory responses
Interleukin-17 Family
- Functions primarily as homodimers
- Associated with innate/inflammatory responses
- Secreted by TH17 cells
- Interface between innate and adaptive immune systems
IL-17
Directs TH17 cell development
IL-17A
TH17 and NK Cells
1. Pro-inflammatory cytokine release
Chemokine Family
- signal through G-Protein Coupled Receptors
- Induce chemotaxis by establishing a concentration gradient
CXCL
CXCR
CCL
CCR
XCL OR (CL)
XCR OR CR
CX3CL
CX3CR
Rho- family of small GTPases
- Directs the actin cytoskeleton
- Pivotal in cell motility
Activated Rac
Lamellipodia Formation
- Protrusive;
- Membrane Periphery
- Orthogonal Arrays
Activated Cdc42
Filopodia Formation
- Protrusive
- Membrane Periphery
- Bundled Filaments
Activated Rho
Stress Fiber Formation
- Contractive
- Cell Interior
- Bundled Filaments
Interleukin-1 Family
- Early Inflammatory Response
- Decoy Receptors: Inhibits IL-1 signal
Hematopoietin Family (Class I Cytokine)
- Hematopoietic Development
- B- and T- Cell Differentiation
- Receptor subunit expression
Interferon Family (Class II Cytokine)
Anti-viral Response
Tumor Necrosis Factor Family
- Receptor trimerization
- Apoptosis (or survival)
Interleukin-17 Family
TH17 signaling for an inflammatory response
Chemokines
- Extravasation
- Cell Migration