Peroxisomes

Front 1

What cell types are peroxisomes found in ? What do peroxisomes look like.

Back 1

Peroxisomes are found in all cell types.

They are bounded by a single membrane and have an amorphous matrix.

Human peroxisomes do not have a crystal-like structure.

Can be linked in a network or reticulum during formation

Unlike mito, do not contain own DNA

Front 2

what reaction takes place within?

Back 2

• 25% of EtOh consumption is processed
• O2 is electron acceptor.

H2O2 can react with itself (dismutation) to produce O2 and water.

• Heat produced.
  

Front 3

What is the function of the peroxisomes and

Back 3

• Starts Oxidizing very long chain fatty acids and then transferred to mitochondria.
  

Both Peroxisomes and mito produce AcCoA

• Oxidize bile acids. Cannot be processed by mitochondria.
  
• Accumulation of VLCFAs are diagnostic for peroxisome disorders
  
• Performs 1st step of Plasmolagens<-- phospholipid in myelin (absence--> neurological disease
  
• Synthesize platelet activating Factor (PAF) (similar to Plasmalogens)
  

Front 4

What are the functions of Platelet Activating Factor?

Back 4

• Supports neuronal signaling and migration during development.
  
• Bronchoconstriction
  
• Platelet Aggregation

Front 5

Where do peroximsomes come from?

Back 5

• They bud as precursors from specialized sites on the ER.
  
• Proteins are imported post-trasnlationally from the cytosol.
  
• Targeting signals can be found at N or C terminus. Sufficient for peroxisome targeting.
  

Front 6

Peroxisomal Disorders are divided into two types. What characterizes those types?

Back 6

Single protein/enzyme deficiencies (structure abnormal)

Organelle biogenesis deficiency

Front 7

X-linked adrenoleukodystrophy (XALD)

Back 7

• More sever in males
  
• neurological complication begins at 4-8
• Defective ABC transporter that is involved in the uptake of VLCFAs
• Diagnosed by high serum levels of VLCFAs. Also can induce inflammatory response.

Front 8

Succesful Gene therapy for XALD

Back 8

HSCs from patient were transfected using lentivirus HIV vector which included ABC1 transporter DNA which incorporated into cells.

HSCs were given back to the patient.

Front 9

Zellweger Syndrome

Back 9

Involves defects in peroxisomal biogenesis.

Extensive neuropathy and Hepatic and Renal dysfunction

Accumulate VLCFA