IC Compartments And Protein Sorting 2 Flashcards
SAM Complex
- Sorting and Assemble Machinery
- Translocates beta barrel proteins on the outer membrane
- Inserts/Folds beta barrel proteins in the outer membrane
What helps in FOLDING for the imported HSP70? How?
- HSP 60
- Helps by utilizing ATP
How does bound HSP70 dissociate?
At the expense of ATP Hydrolysis OUTSIDE the Mitochondria
What are the types of Mitochondrial signal sequences?
- N Terminal
- Internal
Shape of SRP
- Rod shaped
- Large Hydrophobic pocket
(Lined with methionines) - Pocket can accommodate HYDROPHOBIC signal seq
What directs proteins to the correct compartment in the Mitochondria?
Signal Sequences
T/F: Proteins need to cross both Mitochondria membranes.
True
Characteristics of SRP
- Made up of 6 diff polypeptides
- Bound to Small RNA molecule
- Cycles b/w ER membrane and cytosol
- Binds to ERSS
What pulls the protein in the matrix?
Mitochondrial HSP70
TIM22 Complex
- Mediates the insertion of a Specific Subclass of Proteins
eg: ATP, ADP, and Pi transporter
What cleaves the signal sequence?
Signal Peptidase
How do the precursor proteins enter the Mitochondria?
How is is maintained?
- Unfolded
- Maintained through interactions with CHAPERONE Proteins
Cystolic HSP70
Characteristics of ER Signal sequences
- Vary in AA seq
- Has 8+ Nonpolar AA in the CENTER
The 3 ATP dependent steps in Transport
- Dissociation of the Bound HSP70
- Protein release of HSP70
- Folding of Protein by HSP60
Mitochondria proteins are encoded where?
Nuclear DNA
What guides ERSS to ER membrane?
- Signal Recognition Particle (SRP)
- SRP Receptor
Transport of HSP70 through TIM is dependent on what?
Membrane Potential
Where do the residues cluster on the helix?
- “+” charged residues cluster on one end
- Hydrophobic residues cluster on the other
Signal sequences form what in the Mitochondria?
AMPHIPHILIC Alpha Helix
Translocators in the Mitochondrial INNER Membrane
- TIM22 Complex
- TIM23 Complex
- OXA Complex
What Complex helps to form PORIN in the Outer membrane? With the help of what?
- SAM Complex
- Chaperones
OXA Complex
Mediates the insertion of proteins synthesized in the Mitochondria
Parts that make up an SRP
- Translational pause domain
- Signal/Seq Binding pocket
- Hinge
- SRP RNA
Translocators in the Mitochondrial OUTER Membrane
- TOM Complex
- SAM Complex