Receptor/ligand pairs

The development of effector T cells following activation by antigen-presenting cells also requires the interaction of another receptor-ligand pair. CD40 molecules on antigen-presenting cells are required to bind... 

Chockalingam K, Chen Z, Katzenellenbogen JA, Zhao H. Directed evolution of specific receptor-ligand pairs for use in the creation of gene switches. Proc. Natl. Acad. Sci. U.S.A. 2005 102 5691-5696. 

Fig. 2 Use of chimeric T1R2 T1R3 receptors to determine regions critical for sweetener response. Responses to human (H, blue), rat (R, red) or human-rat chimeric T1R2 T1R3 receptors to a sucrose, aspartame, or neotame, b sucrose or cyclamate, and c sucrose (Sue) or acesulfame potassium (AceK) in the absence or presence of lactisole (Lac). Equivalent numbers of cells were imaged for each receptor-ligand pair. (Adapted from Xu et al. 2004, with permission. Copyright 2004 National Academy of Sciences, USA)...

Numerical values for the term defined above, can be obtained from information on the equilibrium association or dissociation (Alj) constants for receptor-ligand pairs. These constants are usually defined ... 

Figure 1-4 Dimerisation of a receptor-ligand complex to form a receptor-ligand pair. It is this dimer that produces a signal, which stimulates the cell to grow and divide.

Figure 1-5 The receptor-ligand pair produces a signal that stimulates cell growth.

Figure 1-6 Degradation of the receptor-ligand pair stops the signal for cell growth.

Figure 1-7 The combination of production and degradation dictates the concentration of the receptor-ligand pair.

The account is in balance if your monthly pay in is as much as your monthly withdrawal. If you withdraw more than you pay in, sooner or later you will be in debt. If you pay in more than you withdraw, you make savings. In a way, the onset of cancer could be compared to a decrease in withdrawal from the bank account. If you still pay in the same amount of money every month, but you withdraw less, your savings will grow bigger and bigger. This obviously is similar to what happens in the cancerous cell - it produces the same amount of receptor, but reduces the degradation of the receptor-ligand pair. 

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