1. Jayanti Tokas1, Rubina Begum1, Shalini Jain2 and Hariom Yadav2
Protein kinases : Role in cell signaling & implication in human pathologies
Jayanti Tokas1, Rubina Begum1, Shalini Jain2 and Hariom Yadav2
1Department of Biotechnology, JMIT, Radaur
2 NIDDK, National Institute of Health, Bethesda,MD20892, USA

2. Protein Kinase

3. 30% of all proteins may be modified
518 protein kinase genes=human kinome space
20% of all eukaryotic genes(human genome project)
Approx 30=tumor suppressor
218 genes=human diseases
Approx 100 dominant oncogenes

4. Kinases Protein phosphorylation cell signaling
Reversible protein phosphorylation as a biological regulatory mechanism
Edmond H. Fischer and Edwin G. Krebs
(1992 Nobel Prize for Physiology and Medicine).
Post-translational modification in the cell
• Cell growth/proliferation
• Differentiation
• Viability/survival
• Homeostasis
• Effector function (e.g. cytotoxicity, cytokine production)
• Cell death
‘signal’

6. Signal Transduction and Kinase Pathways
Adaptor proteins
Nucleus
MAP kinase,
• Transcription factors
– Bind consensus sequence on
promoter
– May form complexes
– May itself be transcribed
following cellular activation
Effector enzymes

7. Classification On the basis of amino acid : Tyrosine kinases,
Serine threonine (PKC, Plk,Rho Kinases)
Receptor (EGFR,FGFR,PDGFR)
non receptor (JAK,src,Abl,MAPK)

8. antikinase inhibitors
Tyrosine kinase
structure
function:
Related pathologies
Check points
Serine threonine kinases
Related pathology
Check points
antikinase inhibitors

9. Structure Bioblar structure N and c N-beta sheets C-alpha helix
ATP bind-cleft at intetrsection

10. Mechanisms of Activation of Normal TKs.
How they function:
Mechanisms of Activation of Normal TKs.
May oligomerise
ligand
survival
Differentiation
Motility
Proliferation

11. Control Autoinhihibitory transmembrane interactions
cytoplasmic juxtamembrane region further inhibits the enzyme by interacting with the kinase domain
Autophosphorylation---. reorient critical amino acid residues increasing catalytic activity
inhibitor proteins and lipids
IF CONTROL LOST
Loss of function
Gain of function

12. Mechanisms of TK Dysregulation
PDGF EGF VEGF FGF KL
PDGFR EGFR HER2 c-KIT FGFR3
Overexpression of receptor or ligand

13. EGFR Superfamily with 4 receptors C-ERBB C-ERBB2 C-ERBB3 C-ERBB4
Cell proliferation
Inhibition of apoptosis
Angiogenesis
Cell motility
metastasis

14. carcinogenesis Carcinogenesis: Dysregulation
colorectal cancer, lung cancer(enhanced responsiveness),glioblastoma multiforme(constitutive active)
Dysregulation
Cell proliferation inh of apoptosis angiogenesis metastasis
carcinogenesis
Over expressed & mutated
Deletions(exon 2-7:alternative splicing)
or point mutations(Ile654Val)

15. Check points

16. FLT3 C-KIT PDGFR EGFR HER2
Mutation in receptor tyrosine kinase causing constitutive expression

17. PDGFR Tyrosine kinase fibroblasts,smooth muscles of lung and airways
Mesenchymal cell migration and proliferation
Angiogenesis and blood vessel maintainance
Dysfunction:
Abnormal vasulature irregular diameter leakiness

18. Glioblastoma
Atherosclerosis
Pathological conditions:del(4q12) ; t(4;22)
Adenocarcinoma
Breast
Colon
Prostate
Stomach

19. FGFR(1-4) Cell growth Differentiation Chemotaxis Angiogenesis
Cell survival
SKELETAL SYSTEM
Dysfunction
60 mutations
FGFR2 craniosynostosis syndrom(premature ossification of skull)
Pfeiffer syndrome(additional fingers
FGFR3 achondroplasia(dwarfism)
Gly380Arg Gly375Cys
Carcinogenesis:prostate, cervical ,bladder, colorectal cancer

20. Check points

21. Fusion of TK to partner protein
ABL PDGFR FGFR1
FGFR3 JAK2

22. Bcr-Abl C-Abl Non receptor tyrosine kinase Role:
Regulation of cell cycle,cellular response to genotoxic stress
Apoptosis neuronal development
Regulation :actin binding PI3 binding
C-Bcr localised in cytoplasm during mitosis(role in cell cycle regulation)

23. Related to CML(chronic myeloid leukemia)
Bcr-Abl
t(9:22)
Related to CML(chronic myeloid leukemia)
prevent apoptosis even in the absence of growth factors
Mitogenic signaling
Altered adhesion to matrix
TARGET-imatinim mesylate
mechanism

24. Check points

25. A serine threonine kinase:PKC
Response to
Growth factors
Hormones
Drugs
11 related kinases
Unregulated in GIST
Diagnostic marker therapeutic target
ATP binding domain inhibitors
Erbstatin
Therapeutic targets

26. Targeting Receptor
Monoclonal antibodies
Herceptin, licensed for Her 2 receptor-positive
Breast cancer

27. Small molecular inhibitors
Various protein tyrosine kinase inhibitors
TYRosine PHOSphorylation INhibitors
tyrophosphins
Competitive with substrate(eg.Itaconic acid)
Competitive with ATP(Quinolines)(main thrust)
ATP binding fold more specific

28. 1. How many other kinase targets opened for exploration?
A LOOK AHEAD
1. How many other kinase targets opened for exploration?
2. Majority of kinases remain largely uncharacterized.

29. Current challenges and future directions

30. THANK YOU