Biogenesis of Mitochondria and Chloroplasts III Flashcards
1
Q
Structure
A
- Chloroplasts
- Biogenetic machinery
- CHLORAD
2
Q
Chloroplast - the basics
A
- lens-shaped; complex structure
- ~5 micrometer diameter
- ~100 / leaf
- dominate cellular proteome
3
Q
Chloroplast functions
A
- photosynthesis (oxygen source; biological energy input)
- metabolism (N and S assimilation; lipid, aa, pigment synthesis)
- environment response and signalling (hormone synthesis, gravitropism, pathogen response, freezing tolerance)
- essential
- agri-biotech opportunities
4
Q
Describe the agri-biotech opportunities associated with chloroplast functon
A
- food security (engineering RUBISCO)
- climate change
- bioenergy
5
Q
Plastids
A
- pro plastid
- amyloplast
- aetioplast
- chloroplast
- chromoplast
- leucoplast
- gerontoplast
6
Q
Chloroplast genome generalities
A
- ~100 genes
- ~3000 proteins
7
Q
TOC receptors
A
- multiple isoforms
- C-terminal anchors
8
Q
Toc75
A
- Omp85 superfamily
- 16TM strands
- N-terminal POTRA domain co-ordinates downstream events
9
Q
plastid protein import 1
A
- Attoc33 mutant
- chlorotic, small, underdeveloped; biogenetic and import defects
10
Q
SP1
A
- RING-type Ub E3 ligase
- cytosolic RNF domain
- physically interacts with all tested Toc proteins, but not envelope proteins
11
Q
RNF
A
ring finger
12
Q
sp1
A
- ^^ Toc proteins
- envelope proteins unaffected
- slower ripening
13
Q
sp1oe
A
- xx Toc proteins
- envelope proteins unaffected
- requires PUX10
- faster ripening
14
Q
SP2
A
- chloroplastic beta-barrel protein
- Omp85 superfamily (lacks POTRA domain)
- OEM-localised
- physically interacts with all Toc proteins + SP1
- required for SP1
- required for CDC48
15
Q
CDC48
A
- cytosolic AAA+ ATPase motor
- conserved chaperone
- interacts with all Toc proteins; SP1 and 2
- required for Toc-Ub retrotranslocation
16
Q
CDC48 inhibition:
A
^^ Toc proteins
17
Q
SUMO
A
- UBL
- induced under stress
- often works in conjunction with Ub
- promotes CHLORAD
18
Q
CHLORAD
A
controls Toc protein homeostasis
19
Q
UBLs
A
- ~20 in Eukarya
- Ub-related in 3D structure, sequence
- common beta-grasp Ub fold
- enzymatic cascades
20
Q
Describe developmental CHLORAD
A
- involved in remodelling; plastid-type interconversions
- de-aetiolation: chloroplast
- senescence: gerontoplast
- fruit ripening: chromoplast
21
Q
SP1-type E3 genes
A
1) SP1
2) SPL1 (antagonist)
3) SPL2 (agonist)
22
Q
CDC48 recruitment
A
- UBX cofactor
23
Q
UBX
A
ubiquitin regulatory domain X
24
Q
PUX
A
- plant UBX genes
- 13 in At
25
PUX10
- chloroplastic (YFP)
- UBA and hydrophobic domains
- interacts with SP1, 2 + various Toc (+ poly-Ub Toc via UBA domain)
- ub + retro link
26
UBA
ub-associated
