Mohsen

Slide 22 is the cut off for block 1 Know gap and gep connecxon Gap junctions protein

Peroxisomes

catalase and urate oxidase: oxidatitve enzymes Biogenesis from ER Fission

PEROXISOMES lots in liver

Oxidation Peroxidase

Detoxification Ethanol -> Acetaldehyle -> Acetic acid ADH ALDH

Hydrogen peroxide

Catalase

PEROXISOMES lots in liver

Oxidation of uric acid to 5-hydroxyisourate

Purine metabolism Gene for Uricase acid lost in hominoids nonsense mutation, TGA Uric acid build up Uric acid is a strong antioxidant, aging Tumor lysis syndrome, chemotherapy, hyperuricemia

kidney failure Gout, acute inflammatory arthritis, uric acid crystals

Peroxisomes β-oxidation of long chain fatty acids

catabolism to 2 carbon molecules Biosynthesis of plasmalogens

myelin nerves, cardiovasculature 70% brain myelin

Pentose phosphate pathway

2 enzymes ATP generation Ribose metabolism

Myelination

Peroxisomal Import SS: three amino acids (Ser–Lys–Leu) located at the C-terminus Soluble receptor proteins in the cytosol which recognize the targeting signals docking proteins on the cytosolic surface (peroxins and PEX genes) Import resemble protein transport into the nucleus (folded and oligomeric prots)

PEROXISOMAL DISORDERS Defects in single enzymes Myelination defects Lipid metabolism Acyl-CoA oxidase deficiency

abnormal neurological development skeletal malformation impaired respiration Cataracts Downs Alzheimers Zellweger syndrome defect in importing proteins peroxisomal deficiency

Acyl-CoA

PEROXISOMAL DISORDERS Defects in PEROXINS (PEX genes) -> peroxisome biogenesis diseases (PBDs)

Clinical symptoms Autosomal recessive developmental brain disorders Skeletal and craniofacial dysmorphism, Liver dysfunction, Progressive sensorineural hearing loss Retinopathy Zellweger syndrome (children and lethal) Cerebrohepatorenal syndrome Cells accumulate very long chain fatty acids (VLCFA) Impaired neuronal migration, neuronal positioning brain development. Reduction in central nervous system (CNS) myelin

ER

Endoplasmic Reticulum

Mohsen

Steroid hormone is non polar thus it has a transporter all the time Its target is in the nucleus All translations initiate in cytoplasm except mitochondria It finds methionine and starts making amino acids 5' phosphate 3' cotranslational membrane transportation

Mohsen

SRP: signal recognition particle Its a cytosolic protein It has a ending site that binds to amino acids that come from RER

Mohsen

Sec is always related to SRP

Mohsen

CUTOFF FOR BLOCK 1 Pre protein

ER resident protein is protein disulfide isomerase (PDI) SH on cysteines cysteines in protein domains exposed to either the extracellular space or the lumen of organelles in the secretory and endocytic pathways are disulfide-bonded CA2+ pumps Storage and Ca2+ binding proteins

cysteine