lecture 1 Flashcards
why did cells evolve to have sub-cellular compartments?
- it increases the efficiency of compartments, e.g. is optimum conditions/PH for an enzyme
- it increases specialisations and functions within the cell
- lysosomal compartment protects rest of cell from low PH
How are organelles maintained?
maintained by delivery of components via vesicles and tubules (e.g. retrieval and recycling )
what are the common motifs in membrane traffiking?
- a signal - required for component to go to right place
- coats
- GTPases (regulators)
- recycling
what is clathrin?
a molecular coat - used to shape the plasma membrane and forms clathrin coated pits during endocytosis, which are then pinched of by DYNAMIN.
what are the clathrin like proteins?
COP I- used by cis golgi
COP II - used by ER
What direction do vesicles move in golgi during secretion?
move from CIS golgi to Trans golgi (on way to PM)
What is the point in different types of coating proteins?
it allows specialisation and segregation between different cellular compartments/ different transport
Give some features of small GTPases in membrane traffiking
- They are involved in signal regulation in traffiking.
- small monomeric 21KDa proteins.
- can bind and hydrolyse GTP
how are small GTPases targetting to membranes?
They have post translational lipid modifications which target them to certain sites in membranes
Give some examples of small GTPases
- Rho
- Rac
- cdc42
what happens in Rho mutants?
actin cytoskeleton effected
-constitutively active forms stress fibres
what happens in ras mutants?
constitutivley active- ruffles of filopodia formation
