Cell Signalling basics Flashcards
What are the three main types of effector proteins? And what do they do?
- Cytoskeletal proteins - alter shape and movement of cell
- Gene regulatory proteins- alter gene expression
- Metabolic enzymes - altered metabolism
Name the Four types of INTERcelluar signalling?
- Contact-dependent cell signalling
- Paracrine
- Synaptic
- Endocrine
What are the four main signalling pathway families in Paracrine signalling?
- Fibroblast growth factor - utilises RTK pathway
- Hedgehog family- (desert, Indian and SONIC) involved in embryonic development
- Transforming growth factor- beta (TGF) - cell proliferation
- Wnt family
Describe the common types of Wnt signalling, receptors and one Intracellular signalling protein known to mediate such signalling pathways?
Wnt pathways- 1. Canonical 2. Non-canonical planar cell polarity 3. Non canonical Wnt/calcium pathway
Frizzled G-protein-coupled receptor, directly activates the cytoplasmic phospho-protein Disheveled
What are the two distinct types of signalling pathways? How immediate are they and what general effect do they have on the cell?
- Alterations in protein function and 2. Alterations in gene-expression
1st Is fast, seconds to minutes
2nd is slow, minutes to hours
Both alter the cytoplasmic machinery and —> altered cell behaviour/function
What is Acetylcholine?
ACh is a ubiquitous neurotransmitter involved in the autonomous nervous system, and acts on both the CNS and the Peripheral nervous system
What are three common effects of ACh neurotransmission?
- Decreased Cardiac muscle contraction and force, acts via Muscarinic receptor M2 (activated by Muscarine and ACh) - inhibition of V-gated calcium channels, efflux of K+ hyperpolarisation of neutrons= inhibitory effect and decreased cAMP levels
- skeletal muscle contraction - via ACh receptors, ligand-gated sodium channels activated —> sodium in muscle cells leads to contraction
- Salivary gland secretion - via M1 receptors
What are the 4 most common outcomes of signalling pathways?
- Survival
- Growth and division
- Differentiation
- Cell death - no signals
Draw AcetylCholine!
Not fucking about mate.
Draw the cross section of a typical blood vessel and label appropriately. (Smooth muscle cells, basal lamina, endothelial cells)
Yeah.
What effect does Calcium have on the isoforms of a Adenylate Cyclase? And what activates class 2 and 4 of AC’s?
3 and 5 are stimulated by Calcium
1 and 6 are inhibited by Calcium
And 2 and 4 are stimulated by Beta-Gamma subunits of the activated G protein (coupled to a GPCR)
What is eNOS?
Endothelial Nitric Oxide Synthase. Converts L-Arginine (with NADPH, H, and 02) into Citrulline and NO.
Describe the steps in Vasodilation with associated eNOS.
- AcetylCholine is released from Synapse of surrounding Nerve cells.
- acetylcholine binds and activates Endothelial Nitric Oxide Synthase
- eNOS converts L-Arginine into Citrulline and NO, with NAPDH, H and O.
- NO diffuses from cell membrane to other surrounding cells
- NO binds and activates Guanylyl cyclase producing cGMP
- Increased cGMP levels causes decreased Intracellular Calcium concentrations
- Activation of K+ channels, leads to hyper-polarisation and relaxation
- cGMP-dependent kinase activates Myosin light chain phosphatase, which dephosphorylates Myosin light chains = smooth muscle cell relaxation
Name 5 signal molecules which bind INTRAcellular receptors (hint: RECtv)
Retinoic acid Estradiol Cortisol testosterone vitamin D3
Detail and draw the structure of an archetypal Nuclear receptor. (Hint has 5 domains)
- Transcription activating domain at N terminal
- DNA-binding domain (DB domain)
- The variable sequence hinge domain (links DBD and LBD together)
- The ligand binding domain (LBD)
- The variable C terminal domain, often inhibited by repression proteins
