Transcript Slide 1

An investigation of the importance of the Kinase Hinge
region on the structure and function of selected Tyrosine
Kinases
c-Kit :active in blue, inactive in yellow.
Activation involves a 6.7 degree tilt on the
N-lobe towards the C-lobe
N-lobe
C-lobe
c-Kit : key structural components
Active form of c-Kit : juxtamembrane :green; P loop
:magenta; C (control) –helix :cyan ; C (catalytic) loop :gray ;
A (activation) loop: red
a-C Glu is “in”
DFG Phe is “in”
Inactive form of c-Kit : juxtamembrane :green; P loop
:magenta; C (control) –helix :cyan ; C (catalytic) loop :gray ;
A (activation) loop: red
a-C Glu is “in”
DFG Phe is “out”
Inactive form of c-Kit + Gleevec : juxtamembrane :green; P
loop :magenta; C (control) –helix :cyan ; C (catalytic) loop
:gray ; A (activation) loop: red
Active form of c-Kit: blue ; Inactive form : yellow
The molecular brake and the kinase hinge
Induced fit of STI binding to c-Kit : 1T45 in
yellow, 1T46 in gray
The molecular brake and the kinase hinge
Inactive c-Kit + STI (1T46)
STI induces fit in molecular break
Van der Waals surface detailing the binding pocket for
1T46 + STI ; Red : Ile 653
STI induces fit in molecular break
Solvent accessible
surface for
Inactive c-Kit + STI
(1T46)
Solvent accessible
surface for
Modified c-Kit
(1T46+ brake on
+STI)
Mechanism for release of the molecular brake
through movement of Activation loop involves a similar
interaction between Ile653 and Phe 811
Phylogenetic Tree of Human Tyrosine Kinases
NEK
*EK
**K
***
fes
fer
matk
csk
frk
fgr
fyn
yes
src
blk
lyn
hck
lck
srms
ptk6
btk
bmx
itk
tec
txk
abl2
abl1
epha8
ephb4
ephb3
ephb2
ephb1
epha7
epha6
epha4
epha5
epha3
epha2
epha1
epha
zap-70
syk
fak2
fak1
tnk1
ack1
jak3
jak2
tyk2
jak1
erbb3
erbb4
erbb2
erbb1
itk
alk
ros1
insrr
igf1r
insr
aatk
ptk7
ddr2
ddr1
ror2
ror1
musk
ntrk3
ntrk2
ntrk1
ryk
ron
met
tyro3
axl
mertk
tek
tie
ret
fgfr4
fgfr3
fgfr2
fgfr1 vegfr3
vegfr2
vegfr1
pdgfrb
pdgfra
csf1rflt3
ckit
FES
CSK
SRC
BRK
TEC
ABL
EPH
SYK
FAK
ACK
JAK
EGFR
ALK
ROS
INSR
aatyk
AATYK
PTK7
DDR
ROR
MUSK
TRK
RYK
MET
UFO
TIE
RET
FGFR
VEGFR
PDGFR
Tyrosine Kinases: c-Kit and c-Abl
No such interaction is present in abl since no
h-bond stabilization is needed; molecular brake is off for
hinge region of Inactive abl + STI (1OPJ)
Leu 317 in abl compared
to Ile 653 in c-Kit
Gln 319 in abl compared
to Asn 655 in c-Kit
Inhibition of c-Kit through the
binding of ellipticines
Inhibition of c-Abl through the
binding of ellipticines : competitive inhibition
HO-ellipticine: Blue
MeO-ellipticene: green
ADP: Cyan
Inhibition of c-Kit through the
binding of ellipticines ; OMe-Phe hydrophobic
interaction stabilizing backbone h-bond