Cell Signaling Pathways
Pathway functions
Cell Signaling pathways can control critical cellular functions and play crucial roles in development and immune response.
Cell Signaling
- Cell signaling refers to the translation of an external signal into a cell’s response
- When a ligand binds a receptor, it triggers intracellular signaling relays of secondary messenger molecules
- Many signaling pathways involve proteins called kinases. Kinases can exist in ‘on’ and ‘off’ states of activation
- Many signaling pathays influence gene expression that can be mediated via changes to transcription factors
Pathway functions
Hormone-driven pathways
Estrogen receptor (ER), androgen receptor (AR), glucocorticoid receptor (GR)
Growth factor pathways
PI3K, MAPK, JAK-STAT1/2, JAK-STAT3
Development pathways
TGFβ, Notch, Hedgehog (Hh), Wnt
Immune pathways
JAK-STAT1/2, NF-КB
Aberrant single pathways or cooperation or crosstalk between multiple pathways (MAPK + TGFβ) are know to cause disease.
Aberrant pathway signaling is linked to diseases across almost all major therapeutic areas.
Signaling pathways are extremely dynamic –
requiring a ‘systems’ approach to analysis.
Signaling & Disease
- DNA mutations do not necessarily cause at aberrant signaling, yet aberrant signaling may result in disease
- Cancer cells have constant activation of signaling cells to grow and divide. This often occurs because of mutations in receptors, protein kinases or transcription factors
- Some immunodeficiencies occur because immune cells lack either the receptors for ligands that instruct immune cells to divide and develop the specific kinases that transmit these signals
- Specific target mutations, e.g., PIK3CA are not required for oncogenic signaling and thus may not determine disease progression or drug response
- Untreated cooperative pathways may also drive drug resistance