Week 13
Intracellular Compartments and Protein Sorting
Intracellular Compartments and Protein Sorting
Proteins that are recruited by scaffolding molecules for biomolecular condensates
What is a client molecule?
The major phospholipid of the endoplasmic reticulum and is made of 2 fatty acids and a glycerol 3-phosphate.
What is phosphatidylcholine?
This process allows materials to enter the cell by engulfing them in vesicles.
What is endocytosis?
Engulfment of an aerobic bacterium through membrane fusion, escape of the endosymbiont into the cytosol, and elaboration of internal compartments allowed for the origin of these.
What are intracellular compartments?
The fusing of a vesicle to a different compartment from where they were originally created
What is heterotropic fusion?
The internal space within the endoplasmic reticulum
What is the ER lumen?
ATP-dependent transmembrane enzymes that help "flip" lipids such as phospholipids specifically between the leaflets (from extracellular to intracellular only).
This process moves proteins out of the cell via vesicles that fuse with the plasma membrane.
What is exocytosis.
These short peptide tags at the beginning of a protein act like a molecular address label, directing newly made proteins from the cytosol to their proper compartment inside the mitochondria.
What is an N‑terminal signal sequence?
Process involving double membrane sheets enclosing cytosolic constituents, creating a new compartment
What is engulfment?
Small enclosed vesicles that are formed when cells or tissues are homogenized, breaking the ER into small fragments that reseal
What are microsomes?
The organelle which is major site of oxygen utilization, detoxification of harmful substances, and beta oxidation of fatty acids.
What are peroxisomes?
These proteins help vesicles recognize and fuse with the correct target membrane.
What are SNARE proteins?
Formed when a fatty acid is attached to sphingosine, this lipid serves as the core building block for all complex sphingolipids.
What is ceramide?
This organelle modifies, sorts, and ships proteins to their proper destinations.
What is the Golgi apparatus.
These proteins have N-terminal signal sequences with a second hydrophobic segment near the C-terminus, which is cleaved by a transamidase to allow for an attachment to the new C-terminus
What is a GPI-anchored protein?
A type of transport that proteins use to get transported to the peroxisomes and inserted into the ER membrane by Sec61.
What is vesicular transport?
This small GTP binding protein helps regulate vesicle budding and transport specificity.
What is Rab protein.
These three molecular players team up to shape and then release vesicles - they bend the membrane, provide the pushing force, and perform the final “pinch‑off” of clathrin‑coated vesicles.
What are BAR‑domain proteins, actin polymerization, and dynamin?
Outer membrane mitochondrial protein translocator complex that is required for transport of all proteins needing to get across the outer membrane to intermembrane space
What is the TOM complex?
The 14 sugars of the oligosaccharide involved in N-linked glycosylation
What is 2 N-acetylglucosamine, 9 mannose, and 3 glucose?
A class of protein chaperones that helps to transport unfolded proteins, stabilizes them in their unfolded state while in the cytosol and can pull them into the matrix space of the mitochondria in their unfolded state.
What are Hsp70 chaperone proteins?
This protein coat is responsible for vesicle formation from the Golgi to other destinations in the cell.
What is clathrin?
This biochemical modification helps proteins fold correctly, increases their stability, and serves as a molecular address to guide them to the right cellular destination.
What is the purpose of glycosylation?
This peroxin recognizes the Ser‑Lys‑Leu tripeptide on cargo proteins and delivers them to the peroxisomal membrane before being recycled back to the cytosol by Pex1/6.
What is Pex5?