Ch 12.2 Vesicular transport and trafficking though Golgi

Steps in vesicle trafficking

1. form vesicle from ___ ___

2. transport to ___ ___

3. ___ initial connection with target membrane

4. ___

5. ___

donor membrane, target membrane, tethering, docking, fusion

each step in the vesicle trafficking is regulated by ___ ____ which are GTP binding proteins

G proteins

G proteins are activated when they are bound to ___

GTP

G proteins are inactivated when they are bound to ___

GDP

G protein posses intrinsic ____ activity

GTPase

G proteins will ___ GTP but is is ___

hydrolyze, delayed

G oritein are regulated and can be inactivated by ___

GAP

G proteins are regulated and can be activated by ___

GEF

GEF stimulates the release of ___ allowing the G protein to bind a new ___

GDP, GTP

GAP stimulates the ___ activity

GTPase

To form a vesicle cargo ___ with ____ , ___ protein and activated _ ___ is needed

protein, receptors, coat, G protein

coat proteins induce or stabilize the ___ ____ either inner coat or outer coat

membrane curve

Inner coat proteins are ___ proteins and membrane ___ proteins. They assemble ___

adaptor, scaffolding, first

___ coat proteins polymerize to form a lattice or cage

Outer

Sar 1 is present in the ___ and is a ___ protein. It helps control coat ___

ER, G, assembly

Arf (1-6) is distributed throughout other vesicular compartments and is a ___ protein, it helps control coat ____

G, assembly

Adaptor proteins bind to and concentrate receptor proteins in the ___ membrane and ___ proteins

donor, scaffolding

Adaptor protein _ used for TGN to endosomes

1

AP_ is used for plasma membrane to endosomes

2

major outer coat proteins include

____ found in plasma membrane and trans-Golgi

___ ___(7 different protein) used for cis-golgi and intra-golgi trnasport

___ ___ (4 different proteins) found in ER and form vesicles

Clathrin, COP I, COP II

Clathrin has a ____ shape that allows ___-like/lattice work to be assembled and coat vesicles can form ___ or ___ and looks like a soccer ball

triskeleton, cage, hexagon, pentagon

donor membranes will have ___

GEF

inactove G-proteins (SAr1 and Arfs) are ___ in the cytosol

soluble

Binding GTP ___ the G-protein which then exposes ___ ___ that inserts in the membrane

activates, lipid anchor

the active G-protein then binds and activate ___ proteins

effectors

effectors include ___ proteins and other molecular machinery required for forming ___

coat, vesicles

Dynamin is a ___ protein that assembles in the ___ region and it polymerizes and forms a ___. They stack together and they activate as each other’s ___

G, neck, circle, GAP

Dynamin uses budding/ fission to cut the vesicle off after I performs ___ ___

GTP hydrolysis

Coat disassembly follows G-protein ____

inactivation

Growing vesicles also incorporate a specific GAP which leads to G-protein ___ and is favored by membrane curvature

inactivation

Rabs is a ___ protein and is used in ___ and ___

G, targeting, fusion

Rabs is used in the translocation of the vesicle because they bind to ___ proteins like dynein kinesin and myosin

motor

Rabs regulates tethering by facilitating ____ between tethering proteins

interactions

Rabs also regulate docking by ensuring that ___ pair with ____

v-SNAREs, t-SNAREs

____ is a single polypeptide which contributes a single alpha-helix to the intercalation

V-SNARE

t-SNARE is composed of 2 polypeptides and one anchores in the ___ ___ and contributes to a single alpha-helix to the interaction and the other one is ___ and contributes 2 alpha helices to the interaction

target membrane, soluble

SNARE interactions are like a ___ between v-SNARE and t-SNARE from N-term to c-term to produce a ___ ___ bundle. It brings the two fusing membranes into ____ proximity

zipper, four-helical, nanometer

Vesicle will fuse and end up in target membrane and includes ____ and ___ proteins

phospholipids, transmembrane

SNARE pair assembly involves ___, ____, ____

NSF, SNAP, SNARE

___ proteins that possess a sorting signal is a sequence of AA that specifies where the protein is to be located

soluble

transmembrane protein that posses a sorting signal act as ___ ___

cargo receptor

Soluble proteins that have no sorting signal will be ____

secreted

Other soluble proteins whose normal home is the ER maybe be randomly collected and transported to the golgi which is referred as ___ ___

bulk flow

ER-resident proteins are retrieved because they have a ___ signal ex. KDEL or KKXX at their c-term , a ____ at the cis-golgi bonds these sequences and leads to their ____ in vesicles for return to the ER

retrieval, receptor, accumulation

Most ER-resident proteins posses a ER ___ signal = RXR

retention

in the ER exit site (ERES) COPII localizes to the ___ region and act as a ____ to regulate cargo movement from the ER into the ERES

neck, gatekeeper

Cargo is transported from ER to Golgi by ___ ____ ___ structures derived from ER exit sites. ___ escorts the detached, tubular structure on its way to joining the golgi apparatus

pearled tubular transport, COPI

Golgi functions are the modification of _____ oligosaccharides, addition ____ oligosacharides, ____ of lysosomal enzymes and sorting of cargo at the ____-____

N-linked, o-linked, phosphorylation, trans-golgi26

At golgi protiens migrate from ___ to ___ and are modified by ___ that are specific to each cisterna. proteins are assorted at ___

cisterna, cisterna, enzymes, TGN

addition of o-linked oligosaccharides is the addition of ____ one at a time. Some may have only a few and some may have hundreds (___)

carbohydrates, proteoglycans

Phosphorylation of lysosomal enzymes

enzymes in the cis-Golgi GlcNAc-1-phosphate to C #_ on a mannose residue on the lysosomal enzymes

an enzyme in the medial-golgi removes the ___ leaving the phosphate behind

produces a signal ____ on each lysosomal enzyme

receptors at the trans-golgi network bind ___ and accumulate the lysosomal enzyme into the vesicles for transport to endosomes

6, GlcNAc, M6P, M6P

in Stationary cisterna Model the proteins move from cisterna to cisterna in vesicles by ___ transport they bud and fuse at the edge of the other ___ and if they move forward they are returned by ___ (reverse direction) transport

anterograde, cisterna, retrograde

in the cisternal maturation model proteins arrive at cis face from the ER. Cis cisternae matures to ___ cisterna as it accumulates enzymes being transported there from the medial Golgi by ___ transport. As cisterna matures to become medial, enzymes that belong in the cis cisterna are transported back by ___ transport. Non-golgi proteins migrate forward with each maturing cisterna and are exposed to the different Golgi ___ sequentially

medial, retrograde, retrograde, enzymes

At trans-golgi network the ER-resident protein shave already been ___. Golgi-resident proteins are all ___ proteins and these are___ ___ into vesicles at the trans-golgi. Proteins that remain to be secreated and lysosomal proteins are collected into ___ vesicles.

retrieved, transmembrane, not sorted, clathrin-coated