Test 3 - Lecture 23 Flashcards
The Golgi Apparatus -
Regulated pathways include release of ______ from _________ ______ and _________ from nerve cells.
hormones
endocrine cells
neutotransmitters
The Golgi Apparatus -
These proteins aggregate in the ________ network and are packaged in ________ granules.
trans - Golgi
secretory
The Golgi Apparatus -
The granules store their contents until signals direct their ______ with the ______ membrane.
fusion
plasma
In _______ cells of the epithelial tissue, plasma membranes are ______
into ______ _______ and _______ ______ , each with specific proteins.
polarized
divided
apical domains
basolateral domains
Proteins leaving the ______ Golgi network must be selectively packaged and transported to the correct domain.
trans
______ and plant cells lack lysosomes.
Yeast
Proteins are transported from the Golgi to the ______
vacuole
A yeast vacuole
- Same functions as a _______
- _______ storage
- Maintaining _____ pressure
lysosome,
nutrient
turgor
Proteins are directed to vacuoles by short _______ ________.
peptide sequences
The selectivity of vesicular transport is key to maintaining the functional _________ of a cell.
organization
Vesicles must recognize and fuse only with the appropriate ______ membrane.
target
Understanding the mechanisms that control vesicular transport is a major area of research in ____ _______.
cell biology
Three experimental approaches have been used:
- ______ of yeast mutants defective in protein transport and ______
- Reconstruction of vesicular transport in cell - ______ systems
- _______ analysis of synaptic vesicles
- Isolation
Sorting - free
- Biochemical
Yeast mutants can be defective at various stages of protein _______ (sec mutants), or are unable to transport proteins to the ______, or retain resident ____ proteins.
secretion
vacuole
ER
1.Isolation of mutants led to molecular _____ and analysis of corresponding genes and _______ of proteins.
cloning
identification
- Reconstituted systems (in vitro):
Enabled isolation of transport proteins, study of the transport process, and functional analysis of the ______ identified by ________ in yeasts.
proteins
mutations
- Synaptic transmission in neurons is a specialized form of _______ secretion.
Synapse: junction of a ______ with another cell.
Chemical neurotransmitters are stored in the neuron in ______ _______.
regulated
neuron
synaptic vesicles
Transport vesicles with secretory proteins are coated with ______ ________.
coat proteins
The coats assemble as the vesicle buds off and are removed in the _______ before it reaches its target.
cytosol
The vesicles fuse with the target membrane.
______ their cargo,
Insert their membrane _______ into the ______ membrane
Empty
proteins
target
Three families of vesicle coat proteins:
1. _____ - ______ ________ carry proteins from the __ to the _______ and on to the Golgi apparatus.
COPII - coated vesicles
ER
ERGIC
Three families of vesicle coat proteins:
2. _____ - ______ ______ bud from the ERGIC or Golgi and carry their cargo back, returning proteins to _______ compartments.
COPI - coated vesicles
earlier
Three families of vesicle coat proteins:
3. _____ - ______ _______ transport in _____ directions between the trans Golgi network, endosomes, lysosomes, and plasma membrane.
Clathrin - coated vesicles
both
Formation if a clathrin - coated vesicle.
Formation of coated vesicles is regulated by small ___ - _____ ______ (ARF1 and Sar1) related to Ras and Ran.
GTP - binding proteins
Formation of a clathrin - coated vesicle
the GTP - binding proteins recruit ______ proteins that mediate vesicle assembly by interacting with _____ proteins and with _____ proteins.
adaptor
cargo
coat
Fusion of a transport vesicle with its target:
1. The vesicle must \_\_\_\_\_ the correct target membrane. 2. Vesicle and target membrane must \_\_\_\_\_, delivering the contents to the \_\_\_\_\_ \_\_\_\_\_\_\_.
- recognize
- fuse
target organelle
Interaction between the ______ vesicles and the _____ membranes is mediated by ______ factors and small - GTP binding proteins ( ___ proteins).
transport
target
tethering
Rab
Vesicle ___ _____ in the active GTP - bound state bind membrane ______ ______.
Rab proteins
tethering factors
Tetherign factors also bind coat proteins, and may stimulate formation of ______between transmembrane proteins called ______.
complexes
SNAREs
Formations of complexes between _____ and target _____ is required for fusion.
vesicle
SNAREs
_____ - ______ pairing provides the _____ to bring the two bilayers close enough to destabilize them and fuse.
SNARE - SNARE
energy
SNARE proteins have a central _____ - ____ domain.
This domain binds to other _____ - _____ domains and _____ the SNAREs on vesicle and target membranes together.
coiled - coil
coiled - coil
zips
This brings the ___ membranes into ____ contact and leads to fusion of the lipid bilayers.
two
direct
- To initiate fusion, Rab/GTP on the ______ ______ interacts with the effector proteins and _ - ______ to assemble a pre - fusion complex.
transport vesicle
v - SNAREs
- A different ___ protein on the target membrane organizes other effector proteins and _ - ______.
Rab
t - SNAREs
- The ______ proteins link the membranes by protein - protein interactions (tethering).
effector
- Tethering simulates Rab/GTP _______ brings the _____ - _____ domains of the SNAREs together where they bind tightly.
hydrolysis
coiled - coil
- After membrane fusion, a protein complex (NSF/SNAP complex) _________ the SNAREs, allowing them to be ______.
disassemles
reused
