Chemical Signal Transduction - Lecture 9 Flashcards
Chemical Signal Transduction Goal
Change overall profile of cellular protein/enzymatic activity
Amplifiaication of lipophilic hydrophobic messengers
Step 3: Hormone/receptor complex can cause many mRNA to be formed
Step 5: Many proteins are formed from each mRNA
Signal Transduction - Hydrophilic Messangers (G-proteins)
- G-protein associated with each receptor
- cAMP is second messenger
- Kinase phosphore lets a target and uses ATP as the phosphate donor
Signal Amplification - Hydrophilic Messengers
Phosphodieterase down cAMP very rapidly (1 to 10s to 100s to 1000s)
Signal Transduction - Hydrophilic Messenger ex. During exercise
- Epinephrine
- Increase cAMP formation
- Activate Protein kinase A
- Activates hormone sensitive lipase
- Activates lipolyses and release of fatty acids to provide fuel during exercise
Water-soluble - Chemical classes
Amino acids, amines, peptides
Fat-soluble - Chemical classes
Steroids, thyroid hormones
Water-soluble - Storage in secretory cell
Secretory vesicles
Fat-soluble - storage in secretory cell
None
Water-soluble - Mechanism of secretion
Exocytosis
Fat-soluble - Mechanism of secretion
Diffusion
Water-soluble - Transport in blood
Dissolved
Fat-soluble - Transport in blood
Bound to carrier protein
Water-soluble - Location of receptor
Plasma membrane
Fat-soluble - Location of receptor
Cytosol or nucleus
Water-soluble - signal transduction mechanism
- open/close ion channels
- activate membrane-bound enzymes
- G proteins and second messenger system
Fat-soluble - signal transduction mechanism
After transcription of mRNA (after protein synthesis)
Water-soluble - time of onset response, duration of response and half-life
Fast, short and short
Fast-soluble - time of onset response, duration of response and half-life
Slow, Long and Long
Neuron System - Secretory Cell
Neuron
Neuron System - Target Cell
Neuron, muscle or gland
Neuron System- Messenger
Neurotransmitter
Neuron System - Pathway for communication
Across Synapse
Neuron System - Basis for specificity
Receptors on postsynaptic target cell
Neuron System - Time to onset effect
Immediate
Neuron system - Duration of effect
Brief
Endocrine System - Secretory Cell
Endocrine Cell
Endocrine System - Target Cell
Most cell types in body
Endocrine System - Messenger
Hormone
Endocrine System - Pathway for communication
Via Bloodstream
Endocrine System - Basis of specificity
Receptors on target cells throughout body
Endocrine System - time of onset effect
Delayed
Endocrine System - duration of effect
Long
Classic Endocrine Tissues of the Body
- Hypothlamus
- Anterior pituitary
- Adrenal Glands
- Pancreas
- Thyroid
- Sex organs
- Kidneys
Fluid Secretion into Lumen
- Maintining normal fluid levels
- Too much loss can lead to diarrhea
- Cl- and Na+ pumps are regulated by a protein kinase
Cholera Toxin and Life Threatening Diarrhea
Chlolera grows under the mucus layer in the small intestine, activates G proteins and causes effluent of Cl-, Na+ and water
Cystic Fibrosis
- Categorized by a homozygous mutation in the CFTR gene
- Could protect against the severe loss of fluid that occurs due to th cholera toxin
- Hétérozygote advantage: more likely to pass on CF gene to their offspring
