pls 623: physiology of plants ii spring semester 2014 jan smalle (jsmalle@uky.edu)jsmalle@uky.edu
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PLS 623: Physiology of Plants II
Spring Semester 2014
Jan Smalle (jsmalle@uky.edu)
Journal club format
Why?
- Practice how to prepare papers and express ideas correctly.
- Training in science debate.
- Practice presentation: research seminar.
TARGETED PROTEIN DEGRADATION
Lectures: January 15, 17
Exam: January 22
Central dogma of genetics
Central dogma of genetics
Regulation of an organisms differentiation and responses to the environment are the result of changes in gene expression.
OLD THEORY: Regulation of gene expression is predominantly controlled at the transcription level.
NEW THEORY: Regulation of gene expression is the result of a combination of protein synthesis (transcription/translation) and protein degradation controls.
DNA RNA PROTEIN
Light
Light responses
EXAMPLE Day/night cycle: day light activates gene expression
DNA RNA PROTEIN ????
Dark
Light responses ?
Day/night cycle: During night time, light-inducible genes are down-regulated
However, regulatory proteins that promote the light response need to be removed in the dark. Otherwise, they would interfere with the dark response.
PhotomorphogenesisHY5: a transcriptional activator of photomorphogenic development
5 days old Arabidopsis seedlings grown under a range of light intensities
Light intensity
(Osterlund et al., 2000)
Western blot using HY5 antiserum
Ethylene signalingEIN3: a transcriptional activator of ethylene responses
4 days old Arabidopsis seedlings grown in the dark on a range of concentrations of the ethylene precursor ACC
(Guo and Ecker, 2003)
Western blot using EIN3 antiserum
Proteolysis
Errors: Misfolded: Cleaved: AA supply: Regulation:
PRQTEIN PRO
T
EIN
PRO + PROTEIN
PROTEIN
PR
OT
E
IN
PROPROTEIN
PR
QT
E
IN P
R
OT
E
IN
PROTEIN
PROTEIN
PR
OT
E
IN
Non-specific Proteolysis
PROTEIN
PR
OT
E
IN
PROTEIN
PR
OT
E
IN P
R
OT
E
IN
PROTEIN PROTEIN
PR
OT
E
IN
PROTEIN
PR
OT
E
IN
PROTEIN
PR
OT
E
IN
Specific or Targeted Proteolysis
PROTEIN PROTEIN PROTEIN
PR
OT
E
IN
PROTEIN PROTEINPROTEIN
Conditional Proteolysis
PROTEIN PROTEIN PROTEIN
PR
OT
E
IN
PROTEIN PROTEINPROTEIN
DARK
Conditional Proteolysis
PROTEIN PROTEIN*Kinase
Phosphatase
PRO
TE
IN
Many cases of conditional proteolysis involve secondary modifications of target proteins. For example: phosphorylation/dephosphorylation.
Conditional Proteolysis
PROTEIN PROTEIN*Kinase
Phosphatase
PRO
TE
IN
Many cases of conditional proteolysis involve secondary modifications of target proteins. For example: phosphorylation/dephosphorylation.
Conditional Proteolysis
PROTEIN PROTEIN PROTEIN
PR
OT
E
IN
PROTEIN PROTEINPROTEIN
Signal
Receptor
*
X?
[Vierstra, 2003 TIPS]
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