Structural Basis for Fibroblast Growth Factor Receptor Activation

1
Structural Basis for Fibroblast Growth Factor
Receptor Activation
Moosa Mohammadi, Ph.D. Department of
Pharmacology New York University School of
Medicine mohammad_at_saturn.med.nyu.edu
2
Fibroblast Growth Factors

• FGFs constitute the largest family of ligands in
  man.

• FGFs regulate growth and differentiation of wide
  array of cells. They
• play essential roles in embryonic events such as
  mesoderm induction,
• morphogenesis and organogenesis and angiogenesis.

• A common feature of all FGFs is their ability to
  interact with heparin.

• FGFs are monomeric ligands and require heparin
  or heparan
• sulfate proteoglycans to induce receptor
  dimerization.

• FGFs have globular core domain known as
  b-trefoil fold.

3
FGF Family
4
(No Transcript)
5
FGF1
FGF2
FGF4
FGF9
FGF10
FGF12
6
B-trefoil fold
7
Receptor Tyrosine Kinase Family
8
FGFR Architecture
9
Alternative Splicing
10
(No Transcript)
11
(No Transcript)
12
Protein Core
Heparan Sulfate Heparin
13
Chemical Structure of Heparin
14
Requirement for Heparin Sulfate Proteoglycans
15
Heparin-linked FGF1 Dimer
16
VEGF-Flt1 Dimerization
17
Questions we addressing

• Molecular mechanism by which FGF and heparin
• induce FGFR dimerization.

B) Molecular basis for FGF-FGFR binding
specificity.
C) Structural basis for FGFR activation in human
disease.
18
Molecular mechanism by which FGF and
heparin induce FGFR dimerization
19
FGFR Architecture
20
Hexasaccharide Can Induce FGFR Dimerization
21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
(No Transcript)
25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28
(No Transcript)
29
(No Transcript)
30
(No Transcript)
31
(No Transcript)
32
(No Transcript)
33
(No Transcript)
34
(No Transcript)
35
(No Transcript)
36
(No Transcript)
37
Sucrose Octasulfate (SOS)
38
SOS can dimerize FGF-FGFR complex
39
Crystal structure of the FGF-FGFR-SOS complex
40
FGF-FGFR-SOS complex
FGF-FGFR-heparin complex
41
SOS imitates heparin in dimerizing FGF-FGFR
complex
42
Selectively desulfated SOS analogs fail to
dimerize FGF-FGFR complex
43
An autoinhibitory role for D1 and Acid Box
In the absence of FGF ligand, receptor is in a
closed autoinhibited state. The flexibility of
D1-D2 linker allows the highly negatively
charged Acid Box to engage in favorable
electrostatic interactions with the highly basic
heparin-binding (HBS) site in D2. Moreover, D1
is interactive with D2-D3 region and occludes
ligand binding and/or receptor dimerization..
The AB/HBS and D1/D2-D3 interactions synergize
for sustainable to occur.
44
D1 and the D1-D2 Linker Interact with D2-D3 and
Inhibit the FGF1 and Heparin Binding Affinity
of FGFR3c
D123 binds FGF1 and heparin with a 4 and 5.7-
fold lower affinity relative to the D23 isoform
Kd 230 nM
Kd 930 nM
In both cases the reduced affinity appear to be
due to a reduction in association kinetics
Kd 788 nM
Kd 4.5 ?M
Kd 20 ?M
45
Molecular basis for FGF-FGFR binding specificity
46


FGF10

FGF2


FGF1
FGFR1c
FGFR2c
FGFR2b
47
bB'- bC loop
bF- bG loop
bC- bE loop
48
(No Transcript)
49
FGF2-D3 Interface
K21
bB'- bC loop
D282
V88
Q56
bF- bG loop
Q284
E58
V316
R60
F17
D320
bC- bE loop
I287
50
FGF1
FGF2
FGF10
FGF2
bC- bE loop
FGFR1c
FGFR1c
FGFR2c
FGFR2b
51
FGF1
bC- bE loop
FGFR1c
52
FGF10
FGF1
FGF2
FGF2
FGFR2b
FGFR1c
FGFR1c
FGFR2c
53
FGF1
FGF2
FGF2
FGF10
FGFR1c
FGFR1c
FGFR2c
FGFR2b
54
FGF10-FGFR2b Structure
55
(No Transcript)
56
b4
b1
T114
S115
F146
D76
S315
G316
I317
bC'- bE loop
57
(No Transcript)
58
b9
R155
b8
I156
Y345
aN
bF- bG loop
59
(No Transcript)
60
Structural basis for FGFR activation in human
disease
61
(No Transcript)
62
Pfeiffer Syndrome

• Type I
• Pro252Arg mutation in FGFR1
• Normal/mild limb phenotype

63
Muenke Syndrome

• Pro250Arg mutation in FGFR3
• Normal/mild limb phenotype

64
Apert Syndrome

• D2-D3 FGFR2 linker mutations responsible for AS
• 67 Ser252Trp
• 32 Pro253Arg
• Severe limb phenotype

65
(No Transcript)
66
Gain-of-function contacts between P253R FGFR2
mutant and FGF
N111
E108
2.7A
2.9A
L107
3.2A
P253R
67
(No Transcript)
68
Gain-of-function contacts between S252W FGFR2
mutant and FGF
P22
S252W
F21
2.7A
H254
Y281
I257
69
?9
N102
E99
2.71 Å
2.74 Å
R252
?8
L98
3.04 Å
P252R FGFR1c- FGF2
70
FGFR1c-FGF2
Wild-type
P252R
KD 61.9 nM
KD 24.4 nM
---- 25nM ---- 50nM ---- 100nM ---- 200nM ----
400nM ---- 800nM
71
FGFR Dimerization and Activation