Prof' Ding Xue, Ph'D' Department of Molecular, Cellular and Developmental Biology

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Prof. Ding Xue, Ph.D. Department of Molecular,
Cellular and Developmental Biology
492-0271 (office) xue_at_spot.colorado.edu http//be
agle.colorado.edu/labs/xue/index.html
Prof. Kevin Jones 492-1363 (office) krjones_at_colora
do.edu Prof. Jens Lykke-Andersen 735-4886
(office) jens.lykke-andersen_at_colorado.edu
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What is this class?
A different class, how science is created and
done!
Combination of many fields and several model
organisms
Your expectation of us?
Mostly paper discussions with a few lectures.
We will be very informal. Our job is to teach
and encourage you to think and to ask about
Science
Our expectation of you
Read Learn Think Ask
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Requirement

• cell biology, biochemistry, genetics, maybe
  developmental biology
• has time to read
• interested in thinking
• not to be too interested in grades as a senior
• We will not be traditional grader. Effort is 1,
  activity and participation are what we are
  looking for.

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Teaching contents

• Cell signaling and Animal development-- General
  introduction of cell-cell signaling and the
  development of model organisms
• Signaling molecules in cell growth and
  differentiation-- Signals, Receptors, GTPases,
  and others
• Signaling pathways in the development of model
  organisms (yeast, worm, fly, Xenopus, and mouse)
• Signaling in Apoptosis/Programmed cell death

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Grading system

• Three exams (in class) (60)
• Preparation for presenting figures in papers
  under discussion and participation in discussion
  (30)
• Attendance (10).
• Grading in preparation and participation will
  emphasize whether you have read the papers such
  that you can present the figures and your
  willingness to attempt to discuss them more than
  the clarity of how you present and discuss
  information. In other words, our emphasis is on
  getting you to think about, criticize, interpret,
  and discuss scientific experiments without being
  intimidated about speaking up.

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What is cell signaling?

• Mechanisms that one cell uses to communicate and
  influence the behavior of another cell.
• In a broader sense, the signaling could include
  environmental cues received by a cell
• Smell
• Light
• mechanic pressure
• Heat
• Others

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Three ways in which cells communicate with one
another
Slow, less specific But can signal to multiple
cells Signaling strength is distance-dependent
Faster, very specific But only affect few cells
Very fast, very specific Also affect few cells
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Three strategies of cell signaling by secreted
molecules
1) Endocrine
2) Paracrine
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3) Synaptic signaling
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.
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Comparison of endocrine and synaptic signaling
Very Fast
Slow (minutes)
Precise
Specificity depend on ligands and receptors
Not Diluted
Diluted in the blood
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The biochemistry of the cell signaling

• The nature of the signal
• A. Environmental cues
• light, chemicals, mechanical pressure,
  pheromones, food and heat etc.
• B. Cellular signals
• chemicals (Ions), hormones, peptides, lipid,
  growth factors, membrane bound ligand, and gas
  (NO and CO).
• - hydrophilic signals can not diffuse into a
  cell and signal by binding to cell surface
  receptor
• - hydrophobic signals carried by carrier
  protein in the blood and enter cells

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Receptors (the molecule that receives the signal)
1) Ion channel-linked receptors
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
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4) Intracellular ReceptorsSteroid hormone
receptors
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THE DECISION OF LIFE VS. DEATH