Chapter 15 Flashcards
What do extra cellular messenger molecules do?
Transmit messages between cells
Autocrine cell signaling:
Cell has receptors on surface that respond to the messenger
Paracrine cell signaling:
Messenger molecules travel short distances through extracellular space
Endocrine cell signaling:
Messenger molecules reach their target cells through bloodstream
Receptor cell signaling:
On or in target sells receive an extra cellular message
Ligand cell signalling element:
Molecule that binds to receptors
What are signalling pathways?
Consist of a series of protein recruitments, each protein in a pathway alters confirmation of next protein normally by phosphorylation
What is the second messenger system?
Responses of a cell signal is sent through this
What do kinases add?
Phosphate groups
What do phosphatases do?
Remove phosphate groups
What is the purpose of target proteins?
Receive a message to alter cell activity
What is signal transduction?
The overall process of cell signalling
What does protein phosphorylation do?
Change the behaviour of a protein, using different methods
What are some extra cellular messengers?
Amino acids, gases, steroids, eicosanoids, peptides and proteins
What are some receptor types?
G protein coupled receptors, receptor protein tyrosine kinases, ligand gated channels, steroid hormone receptors
What is the largest super family of proteins encoded by animal genomes?
G protein coupled receptors
What do phospholipase do?
Split lipids
What do phospholipid kinases do?
Phosphorylate lipids
What do you phospholipid phosphatases do?
Dephosphorylate lipids
What do protein tyrosine kinases do?
Phosphorylate tyrosine residues on target proteins
What are the two groups of protein tyrosine kinases?
Receptor protein tyrosine kinases and non-receptor protein tyrosine kinases
How are RTK’s activated?
Directly by extra cellular growth and differentiation factors
How are non-receptor protein tyrosine kinases regulated?
Indirectly buy extra cellular signals
What are the two mechanisms for receptor dimerization?
Ligand mediated dimerization and receptor mediated dimerization
What is dimerization?
Brings to kinase domains in close contact for trans auto phosphorylation
What is the purpose of autophosphorylation?
Can regulate the receptors kinase activity or serve as binding sites for cytoplasmic signalling molecules
How is signal transduction by RTK is usually terminated?
By internalization of the receptor, primarily through clathrin mediated endocytosis
What are three alternate fates of RTK‘s?
- Degraded in lysosomes
- Return to plasma membrane
- Become part of endosomal signal in complexes and engage and continued intercellular signalling
