32. Adaptin acts as adapter, links cytosolic side of exit receptor to clathrin proteins
33. Clathrin is a triskelion molecule due to its structures, 3 large and 3 small subunits. Amino termini point inward, so when formed together, form hexagonal or pentagonal shape that forms a skeleton around a vesicles like a soccer ball. Stitching is clathrin and the coating is the PM
36. Dynamin recognizes clathrin bud and wraps itself around budding part of vesicle. With the use of GTP, will pinch membrane together and the vesicle is now released.
42. Heatshock protein called hsp70 that is an ATPase, and it uses ATP hydrolysis to remove clathrin and adaptin from the exit receptors that they recognized.
46. Heatshock proteins are a large family of proteins found ubiquitously in cytosol and lumen of the ER/cytosol, but also important chaperone proteins as well as transport proteins.
49. We need to bring in cholesterol to cell . The LDL that contains cholesterol
50. Core of esterified molecules linked to fatty acids surrounded by phospholipid monolayer with cholesterol embedded. Small protein wraps around core as well as PL monolayer. Protein carries recognition sequence for LDL binding receptor.
51. Dalton protein that wraps around core and it carries a recognition sequence signal for LDL binding receptor
58. In endosomes the ph is different enough (more acidic slightly) just enough to dissociate receptor from LDL. LDL is trafficked to lysosomes where hydrolases break it down and release cholesterol into cytosol to be reused by cell and receptor to be reused in the PM
59. This process of endocytosis happens all the time whether LDL Is present or not.
61. Cell can regulate how many receptors are put back in membrane if cholesterol is high
62. Clathrin forms bud off membrane and dynamin pinches off, auxillin and heat shock work to uncoat, fuse with endosomes
63. In endo. Ph is different just enough to dissociate receptor from LDL, so the LDL is trafficked to lysosome where hydrolases break it down into cytosol and receptors are put back in membrane.
64. Mutations that occur in LDL receptors where they are made by cell but cannot bind to LDL in the blood so nothing is brought into the cell
72. The 4 amino acids act as retrieval sequence and when folded properly, exposed and COP I recognizes EXC portion of the KDEL receptor, form a bud, uncoat from bud, targeted back to the ER
73. The Er binds to KDEL protein/same receptor lets go of receptor in ER is because of difference in pH.
78. Another retention signal – arganine, any other amino acid, arginine sequence – used to keep proteins in ER as well and bring proteins back that have been out of ER.
79. Slide 29 – lysosomal proteins into clathrin-coated vesicles.
80. In golgi, after lysosomal proteins have undergone modifications, two signals are recognized by lysosomal targeting receptor
93. As it moves through cis/medial/trans golgi, the phosphorylation acts as a recogntion sequence for enzymes that are gonna come in and cleave spme sugar away, exposing just M6P component of oligosaccharide tag and M6P is recognized as signal sequence that will be trafficked via the receptor to the lysosome.
94. Once fused with lysosome the M6P hydrolase is released into them due to high acidity ph5-5.5
115. Rab GTPase is involved with regulation of movement of vesicles to target membrane because if you remove it, the vesicles wont target and docking doesn’t occur
118. 2 complexes that associate with vesicle that are on the target membrane and link with vesicle that help bring vesicles close to t snares so the v and t associate
119. Coiled coil tethering protein and teherting complex bring vesicle for snares to tether
128. Heatshock protein 70 recognizes N-terminus alpha helix domain that is specific targeting to the mitochndria
129. TOM protein binds to recognition sequence, alpha helix, and links it to the pore in the mitochondira to allow for movement through the memrane (post translational transport)
130. Once protein moves to pore after recognized by receptor, TOM protein fuses with TIM protein (trans. Protein. Of inner mito membra) and makes a single large pore to bring protein to matrix of mitochondria.
131. Process requires energy because the heatshock proteins that keep the protein from folding in cytoplasm, requires the hydrolysis of ATP to be stripped off so protein can be moved through membrane
132. As moves through membran, signal peptidase cleaves signal and protein moves through
133. Hsp70 helps bind and pull protein through TIM and then the Hsp70 needs to be removed to be folded properly
134. Another HSP helps fold protein again using ATP and now we have a properly folded protein in matrix of mitochondria (Hsp60 folds to final conformation)
135. N-terminus alpha helix is positively charged amino acids that have hydrolxylated amino acids in between but can be recognized by this TOM receptor to begin post-translational import
145. Protein in cytoplasm with a NLS (a few basic amino acids clustered along anywhere along protein, when folded, exposed and recognized by proteins in cytosol that target the protein to nuclear pore
146. Importin protein recognizes NLS and carries protein to receptor sites in nuclearporins at nuclear pore and opens up nuclear pore to get into nucleus.