SCIE1106 Lecture Notes - Lecture 27: Guanosine, Aldosterone, Growth Cone
Biochemical Messengers
Monday, 10 October 2016
12:44 pm
How do Cells Change?
• Cells convince other cells to modify their behaviour = change
• Gene-protein expression?
o Transcription factors
• Enzyme activity?
o Phosphorylation (kinase/phosphatase)
o Association (co-activators/co-repressors)
• Secretion?
o Ion channels (Ca2+ trigger)
Extracellular Signalling - Intracellular Signalling:
• Signal molecule release and transport
o Signal molecule - ligand
o Binds to cell-surface receptor protein
• Receptor binding and signal transduction
o Signal molecule initiates effects
o Alter protein function (fast, < sec to mins) or protein synthesis (slow, mins to
hrs)
o Results in altered cytoplasmic machinery
Communication Components:
• Synthesis of signalling molecule (1)
o Protein or lipid base
o Produced within signalling cell, not released straight away
• Signal release (2)
o Stimulus - exocytosis
• Transported to target cell (3)
o Endocrine
o Paracrine
o Autocrine
o Plasma-membrane attached proteins
• Bind cellular receptor (4)
o Signals only affect target cells with receptors for that signal (lock and key)
• Respond to signal (5, 6)
find more resources at oneclass.com
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o Receptor conformational change launches a series of biochemical reactions
within the cell
o Signal transduction cascades - amplify the message and relay it to an effector
protein
• Effect cell function (7)
o Molecular switches activate the effector proteins (switch on enzymes, activate
transcription factors)
o Effector protein change cell function
• Removal of signal - feedback (8, 9)
Extracellular Signalling - Distance:
find more resources at oneclass.com
find more resources at oneclass.com
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
How do cells change: cells convince other cells to modify their behaviour = change, gene-protein expression, transcription factors, enzyme activity, phosphorylation (kinase/phosphatase, association (co-activators/co-repressors) Synthesis of signalling molecule (1: protein or lipid base, produced within signalling cell, not released straight away. Long distance (endocrine: slower, more generalised, plasma ligand dilution necessitates high affinity receptor binding. Short distance (synaptic: faster, more precise, high concentration means low affinity receptor binding works. Extracellular signalling molecules: hydrophilic - proteins/peptides, hydrophobic - steroids, really small - amino acid/nucleoside-derivatives, gases - no, co, sh2, all chemically distinct molecules, hydrophilic and hydrophobic make up the majority of signalling molecules. Stored in secretory granules or vesicles - exocytosis release: vast majority, hydrophilic - bind cell surface receptors and activate intracellular signalling paths, rapid acting, short lived, act quickly (minutes of release, rapidly destroyed (minutes) Steroid hormones: produced by smooth endoplasmic reticulum and golgi apparatus, derived from cholesterol.
