Cell IV Flashcards
Where is the principle site of phospholipid synthesis?
CYTOSOLIC layer of sER
How do phospholipids get from the sER to anywhere else in the cell?
Phospholipid translocators
What is the action of phospholipid translocators?
catalyze the flip-flop of phospholipids from one monolayer to the other
Where are phospholipid translocators found?
membrane-bound enzymes in the sER
Where is Ca stored?
sER
What is the function of atlastin?
a GTPase is involved in constructing and shaping the ER
What happens when there is over-expression of atlastin?
increased ER, lack of golgi
What happens where there is too little atlastin?
ER becomes fragmented
What disease has a deficiency of Atlastin been linked to?
Hereditary spastic paraplegia.
Symptoms include leg stiffness and gait disturbances such as stumbling and tripping. This is due to difficulty in hip flexion and dorsiflexion of the foot.
What are proteosomes?
Large proteases that require ATP
Where are proteosomes located?
In the cytoplasm and the nucleus
What are the three functions of proteosomes?
Proteolysis of:
- Regulating proteins in cell cycle
- Malformed, denatured and damaged proteins
- Antigenic proteins
What are the two major types of proteosomes?
Ubiqitin dependent and not (cytosolic is dependent)
True or false: prion proteins inhibit proteosomes?
True
Defective ubiquitination of proteins is implicated in what disease?
Parkinsons
How are proteosomes implicated in cystic fibrosis?
destroy a competent but slow to fold CFTR
How can proteosomes contribute to CA?
Inhibition of them decreases the degrading of pro-apoptotic factors
Partial inhibition of proetosomes by bortezomib has been effective against what disease? How does this work?
Multiple Myeloma
Inhibits the over destruction of pro-apoptotic factors
What is the main function of the Golgi complex?
Functions as a major sorting and distribution center
How are proteins sorted in the golgi?
By their ‘chemical zip code” (AA or carb attachments)
What are the five ways of protein modification in the Golgi?
Glycosylation Sulfation Phosphorylation Oligosaccharides added Proteolytic cleavage of proteins
How are proteins sent out of the golgi?
In vesicles
Where is the golgi usually found?
Near the nucleus
How many cisternae usually comprise the Golgi?
3-10