Nuclear Import/Export

á      nuclear structure

á      transport cargo

á      nuclear pore

á      targeting signals: NLS, NES

á      Ran GTPase

á      Import/Export receptors

á      FG platform

á      Regulation

ER Translocation

á      Cargo: transmembrane, soluble

á      Post-translational translocation

á      Steps for co-translational translocation

á      N-terminal signal peptide

á      SRP arrest

á      SRP receptor binding

á      ribosome/translocon docking

á      SRP release

á      chaperone and ribosome push/pull

á      signal cleavage

á      Topological Considerations

á      signal peptide

á      signal anchor

á      stop transfer

á      flanking sequences

Biosynthetic Pathway (ER): folding

á      SS

á      glutathione

á      protein disulfide isomerase

á      glycosylation in ER

á      N: en bloc

á      sequence

á      dolichol phosphate

á      O: not en bloc

á      quality control

á      glucosidase

á      glucosyltransferase

á      calnexin,calreticulin

á      unfolded protein response

á      IRE receptor/endonuclease

á      Hac mRNA splicing

á      transcription activation

á       

Biosyn. Path (post-ER): processing, targeting

á      Pathway:  ER->ERGIC->Golgi stack
->TGN-> to either PM or Endosome

á      Targeting mechanisms:

á      Sorting complexes

á      Retention

á      Retrieval Sorting complexes

á      Vesicle vs. Maturation Transport

á      Coats at each vesicle step:

á       concentrate (sort) & form vesicles

á      COPII, COPI, Clathrin/AP1(AP2)

á      Gycosylation in Golgi

á      Targeting to lysosomes (M6PR)

á      Processing of propeptides

Endocytosis

á      Pathway: early endosome->late endosome
->to either lysosome or TGN

á      mechanism

á      coated pit/vesicle formation

á      clathrin/AP2

á      recycling at EE: pH, Vtype ATPase

á      maturation to LE to lysosome

á      examples : LDLR & TfR pathways

Vesicle Transport

á      Budding (vesicle formation)

á      recruitment:

á      low MW GTPase, marks site

á      sorting complex forms at site

á      formation: clathrin, COPI or COPII

á      fission: dynamin: assembly stimulated GTPase

á      uncoating: Hsc70 or sar1 or arf1

á      Docking

á      example is V/T SNARE pair

á      need to recycle

á      Fusion

á      energy barrier

á      role of SNARE pair: core complex formation

á      recycling: NSF ATPase breaks core

 

 

See below for EXAM3

Signaling Overview

á      Physiol. significance

á      Steps in signaling

á      Types of signaling (local & long distance)

á      Hormones: 3 types

á      Receptors: 4 types of surface receptors

á      2nd Messengers: 5 types

á      intracellular signalling molecules (effectors)

á      adaptors, kinases, GTPases

GPCRs

á      pathway (for epinephrine)

á      ligand: epinephrine (aka adrenelin)

á      receptor: 7 TMD bAdR

á      effector #1:

Gs/beta/gamma

á      effector#2: adenylate cyclase

á      2nd message: cAMP

á      effector#3: cAMP dep. kinase

á      4 conformational changes

á      amplification

á      timer control over signaling

RTKs

á      pathway (for EGF)

á      ligand: epidermal growth factor

á      receptor: EGFR tyrosine kinase

á      effector#1: adaptor GRB2(SH2,SH3)

á      effector#2: GEF SOS

á      effector#3: G protein Ras

á      effector#4: kinase Raf

á      effector#5: kinase MEK

á      effector#6: kinase MAP

MAPK cascades

á      MAPKKK->KK-K

á      effectors for wide variety of receptors

á      multiple MAPKs per cell

á      specificity via scaffold proteins

2nd Messengers

á      cAMP

á      eg glucagon, adrenalin control of gluc

á      binds A kinase R subunits

á      C subunits phosph 3 key proteins
GPK, GS, IP
result is increase glucose

á      example of divergence in signaling

á      phosphoinositides

á      generated from PI by PI kinases

á      PI3K is most important,

á      activated by RTKs (& GCPRs)

á      eg insulin stim. of GS

á      PI3K has SH2, makes PI-3,4,5

á      PI-3,4,5 bound by PKB(PH domain)

á      PKB inhibits GSK an inhib. of GS

á      IP3, DAG

á      IP3 generated by PLC

á      binds ER Ca channel (IP3R)

á      increased Ca w/ DAG activate PKC

á      Ca++

á      binds calmodulin (CaM)

á      CaM binds & activates CaMK

Crosstalk

á      pathways activate: PKA, MAPK, PKB, PKC, CaMK

á      specificity: isoforms, localization, & expression

á      divergence: see above

á      convergence: integration, summation

á      feedback regulation:
Receptor phosph & endocytosis

á