- prevents aggregation of unfolded proteins using hsp 70 and GroEL for assistance

- hsp 70 (heat shock protein 70 family)

-found in cytoplasm

-BIB is found int the ER lumin

- newly folded proteins destination is determined by targeting signal

- in mitochondria

- in peroxisomes (protein in folded form)

- in nucleus (protein in folded form)

- in rER (in folded form)

- proteins transported from rER to golgi to lysosomes or plasma membrane

- not all proteins have the same orientation in the membrane

- N-terminus in lumen & C-term in cytoplasm

- labyrinthine membrane where lipids are synthesized & proteins are made

- has a vertebrate nucleus

enzyme used to flip lipids across the lipid bilayer in both directions

- A membrane bound phospholipid translocator

- not specific for phospholipid head groups in ER

- Utilizes ATP to flip phosphatidylserine & phosphatidylethanolamine in one direction

- from extracellular to cytosolic leaflet

- phosphatidylserine gives a negative charge on cytosolic side

only moves phospholipids from cytoplasmic to extracellular leaflet

- contain ribosomes

-continuous with the sER

- membrane targeting uses ER signal sequence @ amino terminus 

- proteins are cleaved by signal peptidase

- proteins gets bound by SRP continuing translation

- Lipid biosynthesis

- Detoxification using the enzyme cytochrome p450

-breaks down barbituate (phenobarbital)

-breaks down ingested alcohol

*note barbituate inhibits complex 1 in mitochondria

- phosphatidylcholine is synthesized from fatty acyl- coenzyme A, glycerol 3-phosphate, and CDP-choline

- where cholesterol is made

(sER proliferates when needed)

1. diffuse to rER to sER

2. By vesicles that bud off & fuse (vesicular traffic)

3. By transfer proteins

- takes lipid to mitochondria bc it doesn't receive vesicular traffic

-both sequester intracellular Ca

-high Ca inside lumen or ER and low in cytoplasm

1. N-terminus peptides cleaved by signal peptidase

2. it receives asparagine 

- this happens in the rER membrane

1. formation of disulfide bonds

- multisubunit complex: heavy & light chains

- insulin receptors have α & β subunits

2. losing trans-membrane domain gaining GPI anchor

3. Protein folding aided by charperones of ER lumen such as BIB

- it gets dislocated back through the ER & binds to ubiquitin 

- then degraded by proteosomes

- caused by a mutation on the CFTR that codes for protein that transports Cl- ions in & out of lumen

- A build up of Cl ions inside cell causes a chemical imbalance

- cell will swell & secretions become very thick

-causes mucus build up in the lungs

(CFTR=cystic fibrosis transmembrane conductance regulator)