Part 3 Flashcards
what is a prr
pattern recognition receptor
what do prrs do
receptors that recognize pathogen-associated molecular patterns (PAMPs). The activation of PRRs is crucial for the initiation of innate immunity, which plays a key role in first-line defense until more specific adaptive immunity is developed
what are the four types of prrs
soluble (free-floating), membrane bound recpt, cytoplasmic receptors, cell signaling
examples of soluble/free floating prrs
complement proteins
examples of membrane bound prrs
TLRs, which recognize viral proteins on cell surface or viral nucleic acids in endosomes
examples of cytoplasmic recepts
NOD, which surveying the intracellular environment for the presence of infection, noxious substances, and metabolic perturbations.
what are complement receptors
Macrophages have complement receptors in order to bind to the complement protein in order to trigger the three complement factors.
what are scavenger receptors
Recognize anionic charges, like LPS.
Seven different types:
Type A: MARCO, SR-A1, SR-A2
Recognize anionic charges in the cell wall components.
Type B: recognize the different densities of lipoproteins.
what are c type lectins
Dectin (b-glucose):
Fungi
Mannose:
Host sugars
Called C-type because they require calcium to activate
Dectin and mannose found in macrophages and neutrophils.
what do all receptors lead to
pathogen being endocytosed
describe the GPCR before lignad binding
GPCR (generic term) is not associated with a G protein
what happens when the ligand binds to the receptor
causes a conformational change in the receptor which enables it to associate with the heterotrimeric G protein.
Heterotrimeric G protein is made up of alpha, beta, and gamma subunits.
Alpha is its own sub unit; beta and gamma are together.
G protein releases GDP and binds GTP (similar to ATP).
Alpha binds to GTP and released GDP
what happens when GTP is bound
G protein dissociates into a and b, g subunits, both of which can activate other proteins.
Alpha = Rac/Rho (proteins)
Rac and Rho lead to respiratory burst; NO and NADPH oxidase.
NO/NADPH oxidase create O2- radicals, O2-, OH radicals, HCl, and H2O2.
All are very toxic to the cell.
SOD degrades the free radicals.
NADPH oxidase is only activated until the last minute.
what does activation of GTPase Rac, Rho, and CDC42 stimulate
chemotaxis or the respiratory burst.
what is respiratory burst
rapid release of reactive oxygen species, predominately from neutrophils, for pathogen killing.
what are granule 1s in neutros
defensins
granule 2 in neutro
cathelicidins and NADPH oxidase
granules 3 in neutro
lysozyme
what are the phagocytic functions
Increased phagocytosis
Fusion with lysosome and granules
Increased cell division
Increased cell growth
Increased production of cytokine, chemotaxis, and release.
Increased cytokines that are specific to inflammation
which cells secrete cytokines
DNM
what distances can cytokines work
Autocrine; stimulation of self.
Paracrine; adjacent cells.
Endocrine; long distances through the bloodstream.
Protein needs to have a long half life and have to overcome the challenge of being secreted into the bloodstream.
families of cytokines
TNF, chemokine receptors, IL1 family, hematopoeitin superfam
what does TNF family do
plays important roles in diverse cellular events such as cell survival, proliferation, differentiation, and death.
Tend to be membrane bound
TNF alpha is the only one that is secreted.
Tend to be in trimers that always bind to receptors with trimers
what do chemokine receptors do
Chemotaxis stimulated
Chemotaxis causes conformation of cytoskeleton
Androgenesis (creation of more blood vessels)
Two categories:
CC (cysteine-cystine)
CXC (cysteine-amino acid-cystine)
GPCRs/fMLP
what does the il1 family do
Inflammation
Describes any cytokine that is produced/used by leukocytes
what does to hematopoeitin fam do
Named by the growth hormone
-CSF means growth hormone
GM-CSF hormone for monocytes and granulocytes
regulate survival, self-renewal, proliferation, and differentiation of hematopoietic pro- genitor cells as well as the functional activities of mature cells
