-
What is a ligand?
A signal that is received by the cell usually resulting in a response.
-
What is a receptor?
A feature on the cell which receives a ligand
-
How does a receptor respond?
- Intrinsically as an enzyme.
- Associated with an enzyme.
- With the cytoskeleton directly.
-
What are some responses to a ligand being received?
- Gene expression
- Metabolism
- Movement
-
What are effector proteins?
They are proteins activated by intracellular signalling proteins
-
What are three types of effector proteins?
- Metabolic enzyme
- Gene regulatory protein
- Cytoskeletal protein (altered cell shape or movement)
-
What types of interactions are there between effectors and cells?
- Direct contact between transmembrane molecules of two neighboring cells
- Paracrine system (local)
- Synaptic (neurotransmitters)
- Cytonemes (thin cytoplasmic extensions releasing hormones)
- Endocrine (via bloodstream)
-
Which type of signalling requires the most signal molecules?
Endocrine
-
Which type of signalling is not soluble?
- Contact dependent
- Maybe Cytonemes?
-
What are three types of signalling responses?
- Quick; < 1 hour; protein de/activation; synaptic
- Slow; 18-24 hours; transcription/translation; endocrine
- Single cell or group in development; autocrine
-
What are four end-results of a cell in response to a signal?
- Survive
- Grow + Divide
- Differentiate
- Die
-
Describe how acetylcholine can cause two different reponses.
- Heart muscle - decreased rate and force of contraction
- Skeletal muscle - contraction
-
What are two types of signals wrt to water?
- Soluble - interact with transmembrane receptors
- Insoluble - interact with cytoplasmic receptors
-
Non-soluble signals affect ___.
transcription
-
What are examples of non-soluble signals?
Vitamin D, estrogen, testosterone, cortisol, estradiol, retinoic acid, and thhroxine
-
Non-soluble signals have a ___ effect due to ___.
- longer-lasting
- their duration in the blood
-
Non-soluble signals enter the cytoplasm by ___.
diffusion
-
Non-soluble receptor responses include ___.
- Early - first 30 min
- Delyated
- Depends on type of protein and timing of synthesis
-
Gene expression regulation falls into two general categories:
-
All nuclear receptors bind as either ___ or ___.
Homodimers, heterodimers
-
An inactive receptor protein is bound to ___ proteins.
Inhibitory
-
Proteins in the primary response can ____.
Activate other proteins for a delayed/secondary response.
-
Describe responses to testosterone.
- Early - male characteristics in development
- Delayed - muscle growth
-
Describe responses to estrogen.
- Early - female characteristics
- Delayed - retention of bone mass
-
What are three classes of cell-surface receptors?
- Ion-channel-coupled (open channel)
- G-protein-coupled (G activates enzyme)
- Enzyme-coupled (intrinsic and associated enzymatic)
-
What are three types of "players" that affect the cell?
- First messengers - ligands such as hormones
- Intracellular signaling proteins
- Second messengers - not unique to one pathway
-
What are examples of second messengers?
cAMP, cGMP, 1,2-diacylglycerol (DAG), IP3, Ca+2
-
What second messengers require ATP?
cAMP, cGMP
-
What second messengers are derived from phospholipids
DAG, IP3
-
Name various proteins/molecules in signalling pathways/cascades.
Anchoring, amplifier, integrator, modular, relay, scaffold, transducer
-
Describe an anchoring protein.
Anchors proteins to a structure at a precise location where needed.
-
Describe amplifier proteins.
Greatly increases signal they receive.
-
Describe Integrator proteins.
Combine signals from two or more pathways before forwarding.
-
Describe modular proteins.
Modify the activity of signaling proteins to regulate signal strength.
-
Describe relay proteins.
Pass messages to the next signaling component in the pathway.
-
Describe scaffold proteins.
Bind to multiple signaling proteins together in a functional complex for quicker and more efficient interaction.
-
Describe transducer proteins.
Convert singal to a different form.
|
|
