Cell Symposia S1 Notes

GCGR

Beili Wu, Shanghai Institude of Materia Medica, CAS

conformational changes of the stalk

structure determination of the GCGR -G protein, Gs and Gi

G protein binding specificity

arrestin-mediated mudulation: tail & core

GPCR-arrestin structure

GCGR-$\beta$arr1 structures adopt a tail conformation

tail conformation is largely distinct from the core conformation

Helix VIII in GCGR-arrestin has a major role in the arrestin recruitment

phospholipid stabilizes the tail engagement

tail conformation mediates cellular trafficking of GCGR and is involved in endosomal G-protein signaling

keypoints

• Structures of the full-length GCGR in four different conformational states were solved
• The stalk and ECL1 are involved in modulating peptide ligand binding and receptor activation
• Intracellular loops play a critical role in determining G protein selectivity
• The tail engagement of GCGR-arrestin mediates cellular trafficking and endosomal G-protein signaling

mGlus: class C GPCRs

Beili Wu, Shanghai Institude of Materia Medica, CAS

Dimerization is mandatory for the function of mGlus

homo and hetermodimers

structure determination of homodimers

inter-subunit conformational changes upon activation

asymmetric dimerization of mGlus is important for receptor activation

class A & B: helix VI activate

structure determination of heterodimers

mGlu3 VFT plays a dominant role in mGlu2-mGlu3 signaling

Asymmetric signal transduction of mGlu2-mGlu3, using mutations

Asymmetric signal transduction of mGlu2-mGlu4

summary

• The cryo-EM structures of mGlu homo- and heterodimers in different conformational states were determined.
• The G-protein-binding site in mGlus, which is mainly formed by the intracellular loops, is distinct from those in all the other GPCR structures
• Asymmetric dimerization is crucial for receptor activation and many provide a molecular basis for the asymmetric signal transduction of mGlus
• Stability of the inactive conformation and G protein interaction pattern of the subunits are determinants of asymmetric signal transduction of the mGlu heterodimers

Hedgehog (HH) and Wnt signaling

Xiaochun Li, The University of Texas Southwestern Medical Center, Dallas, TX, USA

Membrane-bound O-acyltransferase(MBOAT)

screening

Wnt8A is not stable enough to generate 3d model

$Fab^{2C11}$ forms the complex with PORCN

Palmitoleoyl-CoA binding pocket

inhibitors alter the MBOAT activity

about the catalytic mechanism

seeking the Wnt Chaperon

block Wnt7a in ER by adding Bafilomycin, an inhibitor of VATPase

Wnt Chaperon with PORCN

Structure of Wnt7a-WLS-CALR and Wnt3a-WLS-CALR Complex

Glycosylation on the CTD is essential for CALR binding

N-glycan on NC-linker of Wnt2b is essential for CALR binding

Structure comparison with peptide loading complex

Glycosylation on Hairpin3 is crucial for Wnt secretion

Lipid transport mechanism in Gram-negative bacteria

Yanyan Li, Southern University of Science and Technology, China

LPS, Lipoprotein, Phospholipid

Biosynthesis, Transport, Host recognition

LPS reach the outer membrane: MsbA, Lpt A-G

ABC transporter: Transmembrane domain, Nucleotide binding domain(NBD)

Substrate binding domain(SBD), Auxiliary protein

subtrate recognition and specificity?

• Lipid nanodisc incorporation
• EM density of LPS inside MsbA
• EM density of LPS inside LptB2FG
• structure of LolCDE to accommedate lipoprotein
• phospholipid bind in and outside of the Mla complex

substrate movement and conformational transition?

• conformational transition in different ABC transporters
• distinct TMD movements in different ABC transporters
• Conformational change of Mla
• structure dynamics

antibiotic compound screening and design?

• vitrual screening and MD simulation
• biochemical validation LptBFGC whole complex structure

$\gamma$-chain family receptor sharing at the membrane level

Tiantian Cai, High Magnetic Field Laboratory of the CAS

single pass transmembrane protein

common gamma chain

knob-into-hole mechanism for gamma chain and its essential role of this interaction in membrane for IL-9R signaling

disease mutations in TMD of gamma chain and IL-7R

ping-pong reaction mechanism of the lipidation reaction catalyzed by the bacterial lipoprotein N-acyltransferase, Lnt

Martin Caffrey, The University of Dublin Trinity College, Dublin, Ireland

Bacterial Lipoproteins: pre-prolipoprotein, peptidoglycan

mechanism, specificity and drug design

milligrams of Lnt protein

Apo-Lnt structures: active site of apo-lnt