Download Mechanisms of Hormone Action: Steroid

Frontiers in Reproductive Endocrinology
Serono Symposia International
Mechanisms of Hormone Action:
Steroid Hormones
Kelly Mayo
Northwestern University
General Mechanisms of Action
of Steroid and Peptide Hormones
Steroid
Hormone
S
S
P
P
Binds to cell
surface receptor
Hormone-activated
receptor
S
Cytoplasmic or
nuclear receptor
Protein
Hormone
Diffuses across
plasma membrane
Binds to DNA
in target genes
Regulates
gene transcription
S
Non-genomic
effects via
protein -protein
interaction
Changes in
enzyme activity
Receptor-associated
Activation of effector
changes in enzyme activity
enzymes
Generation of
second messengers
Biological
output
Activation of
transcription
factors
P
Biological
output
New mRNAs
Changes in
enzyme activity
TF
P
Biological
output
New mRNAs
Synthesis of
new proteins
Biological
output
Synthesis of
new proteins
Biological
output
1
Select Families of Nuclear Hormone Receptors
Steroid Receptors
Mevalonate Pathway
Estrogen Receptor (ER)
Androgen Receptor (AR)
Progesterone Receptor (PR)
Glucocorticoid Receptor (GR)
Mineralocorticoid Receptor (MR)
Liver X Receptor (LXR)
Pregnane X Receptor (PXR)
Farnesoid X Receptor (FXR)
Non-Steroid Hormones
Thyroid Hormone Receptor (TR)
Vitamin D Receptor (VDR)
Retinoic Acid Receptor (RAR)
9-Cis Retinoic Acid Receptor (RXR)
Ecdysone Receptor (EcR)
Ex-Orphan Receptors
Benzoate X Receptor (BXR)
Steroid and Xenobiotic Receptor (SXR)
Constitutive Androstane Receptor (CAR)
Also RXR, LXR, FXR, PPARs
Peroxisome Proliferators
PPARa (fibrates)
PPARg (thiazolidinediones)
PPAR b/d
Orphan Receptors
ERR family
NGF1-B family
COUP TF family
NGF1-B family
RVR family
SF-1
LRH-1
Dax-1
HNF-4
GCNF
Metabolic Pathways of Nuclear Receptor Ligands
Chawla et al Science 294:1866, 2001
2
Domain Structure of Nuclear Receptors and
Dimerization and DNA Binding Properties
AF-1
1
A/B
ER
DBD hinge
180
C
LBD
263 304
D
E
AF-2
554 595
F
?
LBD
LBD
LBD
RXR
LBD
DBD DBD
DBD DBD
DBD DBD
Homodimeric Binding
to Inverted Repeats
Steroid Receptors
ER, GR, MR, AR, PR
Some Orphan Receptors
Heterodimeric Binding
to Direct Repeats
With RXR Partner
Non-Steroid Receptors
TR, RAR, VDR, PPAR
Monomeric Binding
to Half Site
Orphan Receptors
Ligand Binding Unknown
SF-1, NGF1-B, ERR
DNA Binding by Nuclear Hormone Receptors
Sanchez et al, BioEssays 24:244, 2002
3
DNA Binding by Nuclear Hormone Receptors
ER LBD Homodimer
RAR-RXR LBD Heterodimer
NGF1-B LBD Monomer
Nuclear Receptor Signaling Pathways
H
Cytoplasm
RAPs
hsp90
hsp70
Inactive Receptor Complex
Nucleus
H H
H
Receptor Activation
And Dimerization
Hormone Enters Nucleus
And Interacts with Receptor
Coactivators
H H
Basal
Txn
HATs Factors RNAP
Local Chromatin
Remodeling
Activation of Target
Gene Transcription
4
Nuclear Receptor Coactivators and Corepressors
Coactivators
Integrators/Complexes Corepressors
SRC-1, NCoA-1
GRIP-1, TIF-2, SRC-3
pCIP, ACTR, SRC-3
Many others
CBP, p300
TRAPs, DRIPs
SWI/SNF
pCAF/CARM
bHLH PAS-A PAS-B
SRC-1
RID
1
632
759
NCoR
SMRT
REA
TRUP, SURF-3
AD
Q-rich
HAT RID
907 955
1440
NHR
CBP
Interaction Interaction
LXXLL motifs
Repression Domains
SID1
NCoR
1
92
751
Su(H)D
1035
SID2
RID
RID
1944
2453
Sin 3
NHR
Interaction
Interaction
LXX IXX I/L helices
Coregulators and Chromatin Remodeling
TRAP
DRIP
CBP
Med/ARC
SRC-1
BTFs
HR
CARM-1
RNAP
Sin3
NCoR
HDAC
HR
Inactive
Corepressors
HDACs
Active
Hormone
SWI/SNG
HR BRG/BGM
Coactivators
HATS/MTs
Txn Complexes
Remodeling
Chromatin
Modifying
ATPases
5
Some Nuclear Receptor Ligand-Binding Domains
TR LBD
ER LBD
RAR LBD
RXR LBD
H1
H12
Weatherman et al, Ann Rev Biochem 68: 559, 1999
Structures of Agonist and Antagonist Bound
Estrogen Receptor Ligand Binding Domain
H4
H4
H5
H5
NRII Box
H12
(AF-2)
H12
(AF-2)
H3
H3
ER + Diethylstilbestrol
+ NR Box II Peptide
ER + 4-Hydroxytamoxifen
Shiau et al Cell 95:927-937, 1998
6
Complexities in Steroid Hormone Action: Estrogen
Receptor Genes
Receptor Variants
Interactors
ER-a and ER-b
Diverse promoters
Alternative RNA splicing
Post-translational modifcation
ERR Orphan Receptors
Multiple Mechanisms
Coregulators
Genomic actions
Complex response elements
Non-genomic actions
Tissue specific coregulators
Combinatorial coregulator code
Agonist versus antagonist actions
Tissue-Specific Responses
SERMS
Generation of Diversity in Nuclear Receptors:
Multiple Estrogen Receptor Genes
AF-1
DBD
LBD
AF-2
ER-a
ER-b
Homology:
23%
86%
24%
58%
12%
ER-a predominates:
Kidney, Adrenal, Pituitary, Testis, Epididymis
Equivalent expression:
Mammary gland, Uterus, Bone, Heart, Gut, Brain
ER-b predominates:
Prostate, Ovary, Lungs, Bladder
7
Generation of Diversity in Nuclear Receptors:
Multiple Estrogen Receptor Gene Promoters
Human ER-a Promoters
Potential Implications:
Tissue- or cell-specific ER expression
Developmental-specific ER expression
Alternative splicing of ER transcripts
Kos et al, Mol Endocrinol 15:2057, 2001
Generation of Diversity in Nuclear Receptors:
Multiple Estrogen Receptor Splice Variants
ER-a
ER-b
DBD
ER-a
1
2
3
LBD
4
5 6 7 8
DBD
1
2
3
LBD
4
5 6 7 8
d4
(P,H)
ER-b
1-d3
(P,H)
d3
(P)
d3,4
(P,H)
d5,6
(P,H)
18aa
1-d4
(B)
18aa
2
(P>H)
2-d3
(P>H)
TERP
(P)
Shupnik, J Neuroendocrinol 14:85, 2002
8
Generation of Diversity in Nuclear Receptors:
Phosphorylation of the Estrogen Receptor
In response to estrogen binding:
AF-1
CDK2
DBD
AF-2
MAPK?
Ser Ser
104/106 118
In response to second messenger pathways:
AF-1
MAPK
DBD
Ser Ser
118 167
RSK Ser
236
AF-2
PKA
Lannigan, Steroids 68:1, 2003
Generation of Diversity in Nuclear Receptors:
Interaction with Other Nuclear Receptor Pathways
ERa
ERb
Estradol
DES/OHT
ERRa
ERRb
ERRg
AF-1
DBD
ER
a,b
Natural
Ligands?
ERR
a,b,g
CoA
LDB/AF-2
ERa
RERa
CoR
68%
ERE
AGGTGAnnnTGACCT
37%
ERRE
TnAAGGTCA
ERE
ERRE
Other
ERa
Cell-Specific Responses
ERRa
Giguere, Trends Endocrinol Metab 13:220, 2002
9
Generation of Diversity in Nuclear Receptors:
Multiple Mechanisms of Action
Genomic Actions
E2
E2
E2
Kinase
X
ERE
SP1/AP1
Classical
NF-kB
ERE
X
Ligand-Independent
Non-Classical
Non-Genomic Actions
E2
E2
E2
ER
Novel ER?
Membrane-Bound ER
Novel Estrogen Receptor
Other Proteins
Interaction with Other
Membrane Proteins
Falkenstein et al, Physiol Rev 52:523, 2000
Generation of Diversity in Nuclear Receptors:
Combinatorial use of Coregulatory Proteins
CoActivators
CoRepressors
p160/SRC family
CBP/p300
TRAP/DRIP
“SRA”
NCoR/SMRT
Sin3/HDACs
“REA”
Differential Regulation of Receptors
Tissue-Specific Expression
“Combinatorial Code”
Factor-Specific
Modification
(Phosphorylation
Methylation)
Receptor and Tissue-Selective Effects
10
Selective Estrogen Receptor Modulators (SERMs)
Examples of SERMs:
Tamoxifin (breast cancer)
Antagonist in breast, but agonist in bone/endometrium
Roloxifene (osteoporosis)
Agonist in bone, antagonist in breast/endometrium
Determinants of SERM Action:
Each ligand (SERM) will induce a unique conformation of the estrogen
receptor that impacts its interaction with coregulatory proteins
Each tissue or cell type will contain a unique complement of coregulatory
Proteins and a distinct pattern of activation state of these proteins
Cell-Selective Actions of SERMs
Jordan Cancer Cell 1:215, 2002
11
Additional Pathways of Intracellular Hormone Action
Extrinsic Signals
Arylhydrocarbon Receptor
Nitric Oxide Receptor
Intracellular dioxin receptor
Ligand activated transcription factor
Binds to xenobiotic response element
Cytoplasmic form of guanylyl cyclase
a/b heterodimer with heme cofactor
Increases cGMP and PKG activity
Intrinsic Signals
Sterol Sensing
Oxygen Sensing
P roteolysis of membrane-bound SREBP
bHLH domain regulates transcription
Proteolysis regulated by sterols
Prolyl and Asn hydroxylases regulated by O 2
Hydroxylation regulates HIF-a
Heterodimer with ARNT regulates transcription
Mutations of Hormones, Receptors
and Signaling Proteins in Reproductive Disease
Hormones
FSH
LH
MIS
Delayed puberty, primary amenorrhea in females; male hypogonadism
Luteal insufficiency, infertility in female; delayed puberty, azoospermia in male
Persistence of Mullerian duct derivatives in males
Receptors
GnRH-R
FSH-R
LH-R (Loss)
LH-R (Gain)
Estrogen R
Androgen R
MIS R-II
RET
Partial to complete hypogonadotropic hypogonadism, males and females
Primary or secondary amenorrhea in females, variable/mild oligospermia in males
Amenorrhea or oligomenorrhea in females, range of defects to complete feminization in males
Male-limited precocious puberty, no phenotype in females
Normal puberty, tall stature and unfused epiphyses in male
Many mutations, broad range of phenotypes to complete feminization in males
Persistence of Mullerian duct derivatives in males
Multiple endocrine neoplasia type 2
Signaling Proteins
Gs protein a McCune-Albright Syndrome (gain), male precocious puberty (loss/gain)
Gi protein a Ovarian and adrenal tumors?
Smads
Mutations in many cancers, including Smad4 mutation in seminoma testicular germ cell tumor
Transcription Factors
Dax-1
SF-1
Prop-1
Hypogonadotropic hypogonadism/adrenal failure in male
XY sex reversal/adrenal failure
Variable hypogonadotropic hypogonadism in males and females
12
Emerging and Future Issues in Hormone Action
•Cross-talk between different signaling pathways
•Integration of multiple signals in target cell
•Generation of diverse responses from common stimuli
•Combinatorial codes for signaling diversity
•Spatial regulation of signaling complexes
•Temporal dynamics of cell signaling
•Discovering new signaling pathways
•Discovering ligands for orphan receptors
•Structural solutions to membrane receptors
•Mechanistic structural studies on signaling molecules
•Genetic approaches to hormone action
•Hormone action and human disease
•Rationale drug design
Additional Readings on Steroid Hormone Action
•Evans (1988) The steroid and thyroid hormone receptor superfamily. Science 240:889.
•Tsai and O’Malley (1994) Molecular mechanisms of action of steroid/thyroid receptor superfamily
members. Ann Rev Biochem 63:451.
•Rosenfeld and Glass (2001) Coregulator codes of transcriptional regulation by nuclear receptors. J
Biol Chem 276:36875.
•McKenna and O’Malley (2002) Combin atorial control of gene expression by nuclear receptors and
coregulators. Cell 108:465.
•Katzenellenbogen et al (2000) Estrogen receptors: selective ligands, partners and distinctive
pharmacology. Rec Prog Horm Res 55:163.
•Sanchez et al (2002) Diversity in the mechanisms of gene regulation by estrogen receptors.
Bioessays 24:244.
•Nilsson et al (2001) Mechanisms of estrogen action. Physiol Rev 81:1535.
•McDonnell (1999) The molecular pharmacology of SERMs. Trends Endocrinol Metab 10:301.
•Jordan (2002) The secrets of selective estrogen receptor modulation: cell-specific coregulation.
Cancer Cell 1:215.
•Weatherman et al (1999) Nuclear receptor ligands and ligand-binding domains. Ann Rev Biochem
68:559.
•Kumar and Thompson (1999) The structure of nuclear hormone receptors. Steroids 64:310.
•Chawla et al (2001) Nuclear receptors and lipid physiology: opening the X-files. Science 294:1867.
•Willson and Moore (2002) Genomics versus orphan nuclear receptors: a half-time report, Mol
Endocrinol 16:1135.
•Yudt and Cidlowski (2002) The glucocorticoid receptor: coding a diversity of proteins and responses
through a single gene. Mol Endocrinol 16:1719.
•Gellman (2002) Molecular biology of the androgen receptor. J Clin Oncol 20:3005.
•Conneely et al (2002) Reproductive functions of progesterone receptors. Rec Prog Horm Res 57:339.
13