VesicularVesicular transport transport

Dr. med. habil. Kőhidai LászlóDr. med. habil. Kőhidai LászlóAssoc. ProfessorAssoc. Professor

Depertment of Genetics, Cell- and ImmunoibiologyDepertment of Genetics, Cell- and Immunoibiology Semmelwesi UniversitySemmelwesi University

2008. 2008.

IntracellulIntracellularar ve vessiicularcular tratransportnsport

Communication Communication – intracellular; – intracellular;

- cell-environment- cell-environment

Membrane system Membrane system Uptake of substances and transport to the Uptake of substances and transport to the

place of digestion (lysosomes) - place of digestion (lysosomes) - endocendocytosisytosis Transport of proteins between ER-Golgi and Transport of proteins between ER-Golgi and

to the surface membrane - to the surface membrane - exocexocitózisitózis

Main pathways of vesicular transportMain pathways of vesicular transport

IntracellulIntracellularar ve vessiicculularar tratransportnsport

Bidirectional, transport between Bidirectional, transport between compartment is balancedcompartment is balanced

Continous recyclicling of membrane Continous recyclicling of membrane proteins proteins

Pathway of bPathway of biosiosynthetic-ynthetic-and secretory processesand secretory processes

EEndocndocytosisytosis

RecyclingRecycling

Transport vesicles

Membrane bounded vesicles filled with Membrane bounded vesicles filled with different cargosdifferent cargos•SecretionSecretion

•Lysosomal enzymesLysosomal enzymes

•Components of surface membrane and the ECMComponents of surface membrane and the ECM

Direction of transport is determined by the Direction of transport is determined by the components of the membrane see: donor and components of the membrane see: donor and target compartmentstarget compartments

Molecular bases of vesicular transport

Biosynthetic-secretory and endocytotic Biosynthetic-secretory and endocytotic pathways join 10 or more compartmentspathways join 10 or more compartments

Direction of the transport and fusion are Direction of the transport and fusion are determined by molecular matching determined by molecular matching (receptor/ligand)(receptor/ligand)

Coated vesiclesCoated vesicles

Role of the coat:Role of the coat: Components of the membrane (e.g. Components of the membrane (e.g.

receptors) are concentrated into patchesreceptors) are concentrated into patches

Removal of coated surfaces and formation Removal of coated surfaces and formation of vesicles of vesicles

Types of coated vesiclesTypes of coated vesicles

Clathrin-Clathrin-coated vesiclescoated vesicles

COPI-COPI-coated vesiclescoated vesicles

COPII-COPII-coated vesiclescoated vesicles

Each type of vesicle has its own transportEach type of vesicle has its own transport

We can distinguish the TEM morphology We can distinguish the TEM morphology of the three types of vesiclesof the three types of vesicles

ClathrinClathrin--coated vesicle:coated vesicle: Golgi – surface mamembrane Golgi – surface mamembrane transporttransport

COPI- COPI- andand COPII- COPII-coatedcoated ve vesicles:sicles:rER - Golgi transportsrER - Golgi transports

The building block of the clathrin-coat:The building block of the clathrin-coat: The triskelionThe triskelion

Clathrin-coat Clathrin-coat Triskelion zikk-zakk and globular structural elementsTriskelion zikk-zakk and globular structural elements

Comparison of clathrin compositionComparison of clathrin composition

Light chain

Heavy chain

Protein-protein and protein-lipid associationsProtein-protein and protein-lipid associations under clathrin coatunder clathrin coat

Clathrin binding proteins in MammalsClathrin binding proteins in Mammals

Alberts et all. Molecular Biology of the Alberts et all. Molecular Biology of the cellcell

Releasing of clathrin-coated vesiclesReleasing of clathrin-coated vesicles

Role of dynamin in the process of Role of dynamin in the process of vesicle releasevesicle release

Dynamin is a G-Dynamin is a G-protein, it binds protein, it binds and cleaves GTPand cleaves GTP

Alberts et all. Molecular Biology of the cellAlberts et all. Molecular Biology of the cell

Receptor-mediated Receptor-mediated endocytosisendocytosis

Alberts et all. Molecular Biology of the cellAlberts et all. Molecular Biology of the cell

Receptor-mediated Receptor-mediated endocytosisendocytosis

SummarySummary: Clathrin-coated vesicule: Clathrin-coated vesicule

SummarySummary: : COPIICOPII-coated vesicle-coated vesicle

SummarySummary: : COPICOPI-coated vesicle-coated vesicle

Fusion of vesicle and target membrane (1)Fusion of vesicle and target membrane (1)

Fusion of vesicle and target membrane (2)Fusion of vesicle and target membrane (2)

NSF – N-ethylmaleimide sensitive factorSNAP – soluble NSF attachment proteinSNAP-25 – synaptosomal associated protein 25 kDaVAMP – vesicle associated membrane protein

A significant component of the vesicle-membraneA significant component of the vesicle-membrane fusion: fusion: a protonpumpa protonpump

a subunit –VPH1

d subunitVMA6

4c, c’ and c’’ subunit –VMA3, VMA11, VMA16

Association of main components in membrane fusionAssociation of main components in membrane fusion

SNAP-25 – synaptosomal associated protein 25 kDaVAMP – vesicle associated membrane protein

SNAP-25SNAP-25 VAMPVAMP SyntaxinSyntaxin

n-Sec1-syntaxinn-Sec1-syntaxinkomplexkomplex

SyntaxinSyntaxin

complexcomplex

n-Sec1n-Sec1

Vesicularis transport –Vesicularis transport –„„Budding”Budding”

Vesicularis transport –Vesicularis transport –„„Docking”Docking”

„„Kiss and run” fusionKiss and run” fusion

syntaxin

VAMP

SNAP-25

egyéb

CCP – cl.-coated pitCCV – cl-coated vesic.DCV – dense core vesic.IC – intermed. comp.

Subcellular distribution of SNARE proteinsSubcellular distribution of SNARE proteins

SNARE – soluble N-ethylmaleimide sensitive factor attachment protein receptor

Role of G-proteins in vesicular trasport (1)Role of G-proteins in vesicular trasport (1)

Rab-cycleRab-cycle

Role of G-proteins in vesicular trasport (2)Role of G-proteins in vesicular trasport (2)

S. cerevisiae C. elegans D. melanogaster H. sapiens0

5000

10000

15000

20000

25000

30000F

elté

tele

zett

gén

ek s

zám

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Number of genes responsible for vesicular transportNumber of genes responsible for vesicular transportPhylogenetical approachesPhylogenetical approaches

Evolution of SNARE-sEvolution of SNARE-s

S. cerevisiae H. sapiens