Prof. Ding Xue, Ph.D. Department of MCD Biology. 492-0271 (office) [email protected] http://mcdb.colorado.edu/labs1/xue/MCDB4426/MCDB4426.htm. Why are you taking this class?. Just for fun To get easy credits To learn how to read and think about science
Just for fun
To get easy credits
To learn how to read and think about science
This might be a less boring class
None of above
A different class, how science is created and done!
Combination of many fields and several model organisms
Your expectation of me?
Mostly paper discussions with a few lectures.
I will be very informal. My job is to teach and encourage you to think and to ask about Science
My expectation of you
Long-ranch signaling by secreted molecules
Slow, less specific
But can signal to multiple cells
Signaling strength is distance-dependent
Contact signaling by plasma-membrane-bound molecules
Faster, very specific
But only affect a few cells
Contact signaling via GAP junctions
Very fast, very specific
Also affect a few cells
Specialized endocrine cells secrete hormones, which travel through the bloodstream to target cells
that are distributed widely throughout the body.
Cells secrete local chemical mediators to affect neighboring cells which usually are not the same cells as the signaling cell. To become a local mediator that acts only on cells in the immediate environment, these molecules are rapidly taken up by target cells, destroyed by extra-cellular enzymes, or immobilized by extra-cellular matrix.
Nervous system. Cells secrete neurotransmitters at specialized junctions called chemical synapses; the neurotransmitter diffuses across the synaptic cleft, typically a distance of about 50 nm, and acts only on the adjacent post-synaptic target cell.
Specificity depend on ligands and receptors
Diluted in the blood
Receptors (the molecule that receives the signal)
2) G-protein-linked seven transmembrane receptors
3) Enzyme-linked receptors:
-receptor protein kinases: tyrosine kinases, serine/thronine kinases
-receptors coupled to protein kinases
-protein tyrosine phosphatase receptors
4) Intracellular Receptors—Steroid hormone receptors
THE DECISION OF LIFE VS. DEATH
Signaling by steroid hormone receptors
Signaling by paracrine
All have similar speeds