Molecular PPT 3 Flashcards
(27 cards)
What is a protein molecule that receives chemical signals from outside the cell?
Receptor
What binds and activates the receptor which in turn activates. Intracellular signaling pathways or systems?
A Ligand
What does intracellular proteins do?
Process the signal and distribute it to specific intracellular targets (effector proteins)
What are some examples of effector proteins?
Transcription regulator, ion channels, components of metabolic pathway or parts of the cytoskeleton
Where are receptors located?
Cell surface and intracellular
Which type of receptor is used by hydrophilic signal molecules?
Cell surface receptors
Which type of receptor is used by hydrophobic signal molecules?
Intracellular receptors
cytoplasm and nucleus
Name all of the major types of cell surface receptors?
1) Ligand gated ion channel Receptors
2) G-Protein coupled receptors
3) Enzyme Coupled Receptors
4) integrins
5) Toll-like Receptors
What are the two types of Enzyme Coupled Receptors?
1) Receptor Tyrosine Kinase
2) Cytokine Receptors
When referring to neurotransmitters, G coupled proteins are also called?
Metabotropic receptors
What type of membrane protein is a G coupled protein?
Integral membrane protein
How many polypeptide chains does a G coupled protein contain and what does it do to the plasma?
G coupled protein had a single polypeptide chain that passes in and out of the plasma multiple times
G Proteins bind to specific types of G protein, what are some examples?
Stimulatory(Gs) or Inhibitory (Gi)
What do G Protein Coupled Receptors mediate?
Most responses to signals from the external world, as well as signals from other cells
How many subunits does G Protein have and what do they bind to?
3 different subunits (a, b, Gamma) and they bind directly to the cytoplasmic domain of GPCRs
The a subunit of G Protein is a GTPase, what is bound to it, during its inactive state?
GDP
When G Protein is activated, what occurs?
Activation dissociates B/y complex from the a subunit
What happens when GTPase hydrolyzes GTP to GDP?
Becomes inactive again
How does GPCR play a role in the regulation of ion channels?
They can directly activate or inactivate ion channels in the plasma membrane
How do GPCR activate or inactivate ion channels?
By altering the ion permeability and electrical excitability
What are the most important secondary messengers?
1) Diacylglycerol (DAG)
2) cAMP
3) IP3
4) Calcium
Which of the secondary messengers are water soluble and located within the cytosol?
cAMP, IP3, and calcium
What two things are intracellular receptors?
Both receptors and intracellular effectors of the signal
What happens what an intracellular receptor binds?
Binds to its respective intracellular receptor proteins and alters the ability of these proteins to control the transcription of specific genes
