User:Jamgoodman/sandbox

Examples of primary rewards. Clockwise from top: water, food, parental care and sex.

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In cell biology, there are several signalling pathways. Cell signalling is part of the molecular biology system that controls and coordinates the actions of cells.

The canonical pathway for each signalling pathway is given but there may be multiple non-canonical pathways and negative regulators. Arrows represent activation, which may involve very different mechanisms for different molecules. Homologues of molecules may have different names in different species so the names of the human homologues are given.

The general schema for a signalling pathway is ligand → receptor → adaptor molecules/second messengers → effector protein (kinase/transcription factor)

Signalling pathways can be complex networks with many members and positive or negative regulators. There can be interactions between many of the signalling pathways listed below.

Members of pathways may represent multiple different molecules or isoforms of proteins.

The outcome of a signalling pathway is not determined by the pathway alone but also by the state of the cell including the concentration and location of each member of the pathway and

• PI3K/AKT/mTOR signalling pathway:
  • GF → RTK → PI3K → PIP3 → Akt (note: PI3K also activates PKC) → mTOR
  • GPCR → G protein → PI3K → PIP3 → Akt → mTOR
    • mTOR signalling pathway: mTOR →
• PIP3 → Akt signalling pathway → Akkalpha/mTOR/(inhibition of Bad)
• AMPK signalling pathway: Kinase (CAMKK2 or TAK1) → AMPK
• Eph/ephrin signalling pathway: Ephrin → Eph
• G protein-coupled receptor pathway: GPCR → G protein → enzyme → second messenger → effector
  • cAMP-dependent pathway: Gs coupled GPCR → Gs → AC → cAMP → PKA → CREB
• Hedgehog signalling pathway: SHH ⊣ patched → SMO → GLI
• Hippo signalling pathway: Hpo → Wts → Yki → Scalloped
• Insulin signal transduction pathway: Insulin → Insulin receptor → PI3K pathway / MAPK signalling pathway
• JAK-STAT signalling pathway: Cytokine → cytokine receptor → JAK → STAT
• Notch signalling pathway: notch ligand → notch receptor
• PKC pathway:
  • Gq coupled GPCR → Gq → PLC → DAG → PKC → NFkB/Raf
  • PI3K → PKC → NFkB/Raf
• Ras-Raf-MEK-ERK pathway:
  • RTK → Grb2/Sos → Ras → Raf (MAPKKK) → Mek (MAPKK) → ERK (MAPK) → MNK/MSK/MYC
  • GPCR → G protein → Ras
• TGF beta signalling pathway: TGFB superfamily ligand → type 2 receptor → type 1 receptor → R-SMADs → SMAD4
  • Nodal signalling pathway: Nodal → Activin → Smad2 → TFs (FoxH1/p53/mixer)
• TLR signalling pathway: TLR ligand → TLR → adapter proteins (IKKi, IRAK1, IRAK4, and TBK1) → effectors (NFkB, IRF3)
• EGF signalling pathway: EGF → EGFR → GRB2 → SOS → Ras/Raf/Mek pathway
  • VEGF signalling pathway
• Wnt signalling pathway: Wnt → Frizzled → Dishevelled → GSK3beta → APC → Beta catenin
• FasR/Caspase signalling pathway: Death factor (FasL/Tnf) → FasR → FADD → Caspase 8
• Integrin pathway:

References

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Capsaicinoids

Capsaicin pharmacophore

The class of compounds causing pungency in plants like chili peppers is called capsaicinoids, which display a linear correlation between concentration and Scoville scale, and may vary in content during ripening. Capsaicin is the major capsaicinoid in chili peppers. The pharmacological potency for each capsaicinoid is also listed.

Scoville heat units	Chemical	Potency	Ref
16,000,000,000	Resiniferatoxin	38.4 to 47.6 pM
5,300,000,000	Tinyatoxin
15,000,000 to 16,000,000	Capsaicin, Dihydrocapsaicin	capsaicin: 99 nM (EC50)
9,200,000	Nonivamide
9,100,000	Nordihydrocapsaicin
8,600,000	Homocapsaicin, Homodihydrocapsaicin
160,000	Shogaol
100,000 to 200,000	Piperine
60,000	Gingerol
16,000	Capsiate	290 nM (EC50)