Cell Identity Determined by types and amounts of proteins in the cell Protein identities and amounts...
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Cell Identity • Determined by types and amounts of proteins in the cell • Protein identities and amounts controlled by gene expression • Differential gene expression
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Transcript of Cell Identity Determined by types and amounts of proteins in the cell Protein identities and amounts...
Cell Identity
• Determined by types and amounts of proteins in the cell
• Protein identities and amounts controlled by gene expression
• Differential gene expression leads to cell differentiation
Differentiation
Divide Differentiate
Stem Cells
DifferentiatingCell
Mature Tissue Cell
Blood Cell Differentiation
Regulating Gene Expression
gene
a
b
c
d
mRNA
protein
Gene Expression Controla) transcription
b) processingc) stabilizationd) translation
Cell Must be Signaled to Change
gene
a
b
c
d
mRNA
protein
Gene ExpressionControl
a) transcriptionb) processingc) stabilizationd) translation
Extracellular Signals
1) Growth factors
2) Hormones
3) Cell-Cell contacts
Types of Signaling
Example-Ras Signal Transduction
Zbigniew Walaszek et al, Cellscience Reviews Vol 1, No 3 2005
Ras Signal Transduction
Malorye AllisonNature Biotechnology 26, 509 - 517 (2008)doi:10.1038/nbt0508-509
Malorye Allison Nature Biotechnology 26, 509 - 517 (2008)doi:10.1038/nbt0508-509
Signal Transduction Complexity
http://upload.wikimedia.org/wikipedia/commons/thumb/2/29/Signal_transduction_v1.png/800px-Signal_transduction_v1.png
Cell Division
Fundamental property of living things
Incredibly complicated processCell must ensure coordination of growth, genome duplication and cell division Must not enter duplication cycle unless
resources are plentiful Must not divide before genome is completely
duplicated
Cell Cycle
Division process takes about 24 hours in humans
Signals and Transduction Drives Cell Cycle
Cell Cycle can be Stopped
Example, Tumor Suppressor p53
DNA damage causesp53 to be activated.
p53 blocks cell cycle
How Does Cancer Happen?
Mutations that incorrectly activate any protein in the Ras pathway can cause loss of cell cycle regulation
EGF, ErbB, Ras, Raf, Mek, Erk, Elk, Srf, Fos
But what about p53?
p53 is also Mutated
Over 50% of human tumors have p53 mutations
Multiple Events Required for Cancer
Alterations in the pathway of colon cancer are well known
cropwiki.irri.org/.../2/23/Bioinformatics2.jpg
Bioinformatics Contributes to our Understanding
