Fc Receptor Signaling to the Nucleus

Instituto de Investigaciones BiomédicasUniversidad Nacional Autónoma de México

CARLOS ROSALES LEDEZMA

Receptors for Fc part of IgG

Berken & BenacerrafJ. Exp. Med.1966; 123:119

Macrophage

Ab

Fc Receptor Functions

Mast cell

IgE

FcεR

Macrophage

IgG

FcγR PhagocytosisADCCRespiratory BurstDegranulationInflammatory MediatorsGene ActivationCytokine Production

Human IgG Fc Receptors

FcγRI FcγRIIA FcγRIIB FcγRIIIA FcγRIIIB

CD64 CD32 CD32 CD16 CD16

γ2 α α α α α α-GPIγ2 γ2 β

MacrophageNeutrophilEosinophilDendritic Cell

MacrophageNeutrophilMast CellEosinophilPlateletDendritic Cell

MacrophageNeutrophilMast CellEosinophilDendritic CellB Cell

MacrophageMast CellBasophilsNK CellDendritic Cell

Mast CellBasophil

Neutrophil

ITAM

ITIMAnnu. Rev. Immunol. 1991; 9:457Annu. Rev. Immunol. 1997; 15:203

FcR signaling (~1996)

Nucleus

DNA

IL-1, IL-8TNF

?

Y-kinase

Fc receptor Membrane

NF-κB

NF-κBIκB

Ras signaling

RTK MembraneGAP

Grb2Sos

RasGDP

RasGTP

Raf

SRE

Nucleus

DNAGeneexpression

MEK

ERK

Elk-1

Assay for NF-κB activation

Luciferase

mRNAlucGene

Fc receptorTHP-1Membrane

NF-κBIκB

NF-κB

Dominant negative Ras does not inhibit NF-κB activation

0

1

2

3

4

5

pZIP Ras N17

Luci

fera

se A

ctiv

ity(F

old

Incr

ease

)

MediumIIC

Dominant negative Raf does not inhibit NF-κB activation

0

1

2

3

4

5

6

pCGN Raf 23-284

MediumIIC

Luci

fera

se A

ctiv

ity(F

old

Incr

ease

)

MEK is required for immune complex-mediated NF-κB activation

0

1

2

3

4

MediumIICIIC + PD98059

Luci

fera

se A

ctiv

ity(F

old

Incr

ease

)

FcR signaling

Nucleus

DNA

?

Fc receptor THP-1

NF-κB

NF-κBIκB

Syk

MEK

ERK

J. Biol. Chem. 1998; 273: 27610

GeneExpression

ERK activation requires PI 3-K

-phospho-ERK

MEK activation depends on PI 3-K

PI 3-K is required for NF-κB activation

0

0.5

1

1.5

2

2.5

3

3.5

4

Luci

fera

se A

ctiv

ity

MediumIICIIC + WorIIC + LY

FcR signaling

Nucleus

DNA

Fc receptor THP-1

NF-κB

NF-κBIκB

Syk

MEK

ERK

J. Leukoc. Biol. 2001; 70: 649

GeneExpression

PI3K

Neutrophil Fc ReceptorsFcγRIIA FcγRIIIB

CD32 CD16

α α-GPI

J. Leukoc. Biol. 2005; 15: 203

PhagocytosisCalcium RiseDegranulationRespiratory Burst

Calcium RiseRespiratory BurstActin assemblyIntegrin activation

J. Biol. Chem. 1992; 267: 5265Biochem. Biophys. Acta 1999; 1452: 46

Are FcRIIA and FcRIIIB Signaling Different?

FcγRIIIB

?

PMN

FcγRIIA

Nuclear Factor Activation

PMN

FcγR

mAb

NF-κB

IκB

FcγR

NF-κB

J. Immunol. Meth. 2007; 320: 104

Nuclear Factor Activation

FcγR

NF-κB

NF-κB NF-κB

FITC

FACSJ. Immunol. Meth. 2007; 320: 104

NF-κB Activation

00.5

11.5

22.5

33.5

4

--- IV.3 3G8

Nuc

lear

Sta

inin

g (F

old

Incr

ease

)

Phagocytosis

00.5

11.5

22.5

33.5

44.5

5

FcRIIA FcRIIIB

Fold

Incr

ease

---IV.33G8

FcRIIIB signal to NF-κB is independent of Syk and MEK

00.5

11.5

22.5

33.5

4

IV.3 3G8

Nuc

lear

Sta

inin

g (F

old

Incr

ease

)

DMSOPiceatannolPD98059

Signaling to Nucleus in PMNFcγRIIA FcγRIIIB

SykPI3K

MEK

ERK

NF-κB

NF-κBIκB

PMN

Nucleus

Signaling to Nucleus in PMNFcγRIIA FcγRIIIB

SykPI3K

MEK

ERK

NF-κB

NF-κBIκB

PMN

Nucleus

ERKP

?

P

Nuclear phospho-ERK

00.5

11.5

22.5

33.5

44.5

IV.3 3G8

Nuc

lear

Sta

inin

g (F

old

Incr

ease

)

Nuclear phospho-ERK

ERK

---- 3G8 F(ab’)2 3G8IV.3

p-ERK

Nuclear phopho-ERK is independent Syk, MEK, and PI 3-K

0

1

2

3

4

5

6

DMSO Piceatannol PD98059 Wortmannin

Nuc

lear

Sta

inin

g (F

old

Incr

ease

)

3G8

Signaling to Nucleus in PMNFcγRIIA FcγRIIIB

SykPI3K

MEK

ERK

NF-κB

NF-κBIκB

PMN

Nucleus

ERKP

Nuclear ERK does not change after FcγRIIIB crosslinking

Nuclear ERK

MEK is not present in PMN nucleus

Nuclear MEK

Nuclear phospho-Elk-1

00.5

11.5

22.5

33.5

44.5

IV.3 3G8

Nuc

lear

Sta

inin

g (F

old

Incr

ease

)

Nuclear phospho-Elk-1

p-Elk-1

ERK

---- 3G8 F(ab’)2 3G8

Nuclear phopho-Elk-1 is independent Syk, MEK, and PI 3-K

0

1

2

3

4

5

6

DMSO Piceatannol PD98059 Wortmannin

Nuc

lear

Sta

inin

g (F

old

Incr

ease

)

3G8

FcγR activation of ERK in PMN cytoplasm

FcγRIIA FcγRIIIB

SykPI3K

MEK

ERK

NF-κBNF-κBIκB

PMN

Nucleus

ERK P

?

FcγRIIIB activates nuclear factors in PMN

FcγRIIA FcγRIIIB

NF-κBNF-κBIκB

PMN

Nucleus

ERK P

Elk-1 P

Conclusions

• FcγRIIA and FcγRIIIB signal differently in the PMN

• FcγRIIA induces efficient phagocytosis

• FcγRIIIB induces efficient ERK and Elk-1 activation

• FcγRIIIB signal transduction does not involve Syk, MEK, PI 3-K, Src family kinases, or Tec family kinases

Acknowledgments• Gabriela Sánchez-Mejorada• Elsa Merit Reyes• Erick García• Nancy Mora• Alejandro Ortiz Stern• Georgina Nieto• Melissa Ruiz• Marco Hernández • Selma Rivas• Victor Salas