Are there any additional resources on cell signaling?

Yes! I’m going to recommend Unit 4 from the following free text https://www.nature.com/scitable/ebooks/cntNm-14749010 I used this as the basis for the cell signaling part of today’s lecture, and it’s going to go into the same concepts at greater depth. If you are looking for detailed information on a specific signaling pathway, Cell Signaling Technology is a good place to start https://www.cellsignal.com/.

So, on cell signaling, what is the distinction between the solid and dotted lines? How much evidence do you need to make a dotted connection a solid one?

The short answer is that it depends, but at the minimum, you need one piece of direct evidence from a well-controlled experiment to make a claim about an interaction between two molecules.

Why do we not know the ligands for some receptors? If the existence of a receptor is known, why can’t the ligand be known?

Great questions! Receptors that don’t have known ligands are called orphan receptors – based on their sequence and structure, they are highly likely to be a receptor but we haven’t identified the ligand (yet!). The experimental approach to identifying ligands is not trivial. Here’s a link to a recent review on the current status of identify ligands by studying receptor structure – it’s a good place to get started if you want to learn more. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5341249/

What’s the importance of each receptor type for our CaMPARI experiment?

The short answer is “no specific importance”, and the long answer is “it depends”. I covered the bare minimum basics of the 3 major types of receptors to provide enough background knowledge for you to be able to digest/process what you find in the literature about how your selected drug may influence calcium signaling. I’d like you to be aware of these 3 receptor types and their functions at the following level of detail: 1) ion channels selectively allow ions to pass from one side of a semi-permeable membrane to the other side 2) GPCRs receive a ligand/signal from the external environment and transduce the signal through a complex second messenger system and 3) RTKs are activated when ligand binding causes phosphorylation and trigger downstream signaling cascades.

Where can I learn more about cell signaling diagrams; I’m confused about the whole reception-transduction-response process.

True story… the first time I learned about cell signaling, I decided that “that whole cell-bio thing is too complicated and it’s not for me.” It’s a hard concept to wrap your mind around! The clearest and most succinct resource that I have found on the topic is found at the following open-source text linked below. Unit 4 covers cell signaling concepts, but does rely in part on an understanding of the essential cell bio topics discussed in the first 3 Units. https://www.nature.com/scitable/ebooks/essentials-of-cell-biology-14749010/contents