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I found this picture in my study materials. I think it is too schematic and ignores the big pictures.

enter image description here

I think the thing connected to the hormone is receptor. The second messanger is then connected to the receptor which stimulates the effector cell in the cytosol. The cell then response both to cytosol and to extracellular space. How do you understand this picture?

Do you know any similar pictures which present the same thing but clearer and more exactly?

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up vote 2 down vote accepted

I think the schematic you have there and the one that @Masi posted are pretty good. A better way of getting a grasp of intercellular signaling would be to study a specific hormone and understand how each of the elements in the block diagrams here could vary.

For instance take a look at this diagram from a journal article where they are tinkering with yeast mating factor, one of the first discovered extracellular signaling pathways.

enter image description here

alpha factor and 'ligand' (I assume its not known at this point) bind to their receptors Ste2 and hGPCR respectively. They then activate G protein complexes and both activate the same kinase cascade Ste4/18 -> Cdc42 -> Ste20 -> MEKK/MEK/MAPK/Ste5 which then may activate Far1 (or not) and Ste12. Far1 and Ste12 are migrated into the nucleus to activate genes for cell reproduction.

By actually filling out the boxes in your diagram you can see dozens of different paradigms for how cell signaling may work, and why the diagram you have needs to be so simple. Hope this helps.

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Thank you for your clear answer! – Masi Feb 5 '14 at 16:58
Glad it makes sense! – shigeta Feb 6 '14 at 6:31

I found this picture from my old study materials which I edited little to show the I/e and E/c spaces.

enter image description here

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I think some arrows are missing. Probably, some arrows should go from specific modifications of enzymes or proteins to I/c and E/c. What do you think? – Masi Feb 5 '14 at 13:21

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