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PLS 623: Physiology of Plants II
Spring Semester 2014
Jan Smalle ([email protected])
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.
EXAMPLE
Day/night cycle: day light activates gene expression
Light
DNA
RNA
PROTEIN
Light responses
Day/night cycle: During night time, light-inducible genes are
down-regulated
Dark
DNA
RNA
PROTEIN ????
Light responses ?
However, regulatory proteins that promote the light response
need to be removed in the dark. Otherwise, they would
interfere with the dark response.
Photomorphogenesis
Light intensity
HY5: a transcriptional activator of
photomorphogenic
development
5 days old Arabidopsis seedlings
grown under a range of light
intensities
Western blot using HY5 antiserum
(Osterlund et al., 2000)
Ethylene signaling
EIN3: a transcriptional activator of
ethylene responses
Western blot using EIN3 antiserum
4 days old Arabidopsis seedlings
grown in the dark on a range of
concentrations of the ethylene
precursor ACC
(Guo and Ecker, 2003)
Proteolysis
Errors:
Misfolded:
PRQTEIN
PRO
I Q
TP N
R
E
I O
TP N
R
E
Cleaved:
AA supply:
PROPROTEIN
PROTEIN
PROTEIN
I O
TP N
R
E
PROTEIN
PRO + PROTEIN
Regulation:
I O
TP N
R
E
Non-specific Proteolysis
PROTEIN
PROTEIN
PROTEIN
PROTEIN
PROTEIN
PROTEIN
I O
TP N
R
E
I O
TP N
R
E
I O
TP N
R
E
I O
TP N
R
E
I O
TP N
R
E
I O
TP N
R
E
Specific or Targeted Proteolysis
PROTEIN
PROTEIN
PROTEIN
I O
TP N
R
E
PROTEIN
PROTEIN
PROTEIN
Conditional Proteolysis
DARK
PROTEIN
PROTEIN
PROTEIN
I O
TP N
R
E
PROTEIN
PROTEIN
PROTEIN
Conditional Proteolysis
Many cases of conditional proteolysis involve secondary
modifications of target proteins.
For example: phosphorylation/dephosphorylation.
Kinase
PROTEIN
*
PROTEIN
Phosphatase
O
I
TPRN
E
Conditional Proteolysis
Many cases of conditional proteolysis involve secondary
modifications of target proteins.
For example: phosphorylation/dephosphorylation.
Kinase
PROTEIN
*
PROTEIN
Phosphatase
O
I
TPRN
E
Conditional Proteolysis
Signal
Receptor
X?
*
PROTEIN
I O
TP N
R
E
PROTEIN
PROTEIN
PROTEIN
PROTEIN
PROTEIN
[Vierstra, 2003 TIPS]