Signal transduction crosstalk

Barnard, E.A. (1992) Signal transduction crosstalk. Trends Biol. Sci. 17 367-368. 

Each of these pathways involves a kinase cascade resulting in the phosphorylation and activation of the MAP kinase family member. Each contains a dual phosphorylation site (TEY, TPY, or TGY) and the central residue in the motif characteristic of the class, as shown in Table 8.1. It is evident that cells are endowed with parallel signal-transduction pathways and that they may operate individually or in combination to initiate specific patterns of gene expression. Additionally, crosstalk between the pathways undoubtedly occurs. None of these pathways has a unique function it is more likely that the combination of pathways that are activated (or silenced) together with the... 

EIN2 operating downstream of CTRl is considered a central component in the ethylene signaling pathway and also it is assumed to be a common node mediating crosstalk of multiple hormone signal transduction pathways. " ... 

Houslay MD Crosstalk a pivotal role for protein kinase C in modulating relationships between signal transduction pathways. Eur J Biochem 195 9-27, 1991 Howland RH Thyroid dysfunction in refractory depression imphcations for pathophysiology and treatment. J Chn Psychiatry 54 47-54, 1993 Hoyer D Functional correlates of serotonin 5-HTl recognition sites. J Recept Res 8 59-81, 1988... 

Signaling pathways always possess multiple mechanisms to regulate the intracellular signal transduction. This allows a specific attenuation or termination of the signal. Very often different signaling pathways communicate with one another. This commimica-tion is called crosstalk. 

The existence of a variety in response kinetics and excitatory and inhibitory responses in the same ORN are not easily explained in terms of a single signal transduction cascade. They hint at the possibility of multiple transduction pathways, as has been demonstrated in lobster ORNs (Ache and Zhainazarov, 1995). This could lead to simple forms of stimulus integration at the level of the ORN (Derby, 2000). Do multiple pathways function in complete isolation or is there crosstalk The presence of a variety of reversal potentials in patch clamp studies of Drosophila antennal ORNs suggests that odorants do not all elicit the same transduction mechanism (Dubin and Harris, 1997). What is the evidence in Drosophila for the presence of transduction element of the main pathways, the cyclic nucleotide pathway and the IP3/DAG pathway Is there coexpression in single neurons ... 

Define autophosphorylation and crosstalk as it relates to signal transduction. 

It is very common for proteins that are involved in signaling to be members of more than one signaling pathway. This leads to crosstalk between the pathways. Because of this, the relative concentrations and activities of such proteins may affect the extent to which signaling occurs down the different pathways. This is shown schematically in Fig. 6-10, in which protein 3, which is activated as a consequence of signal transduction from receptor B, can activate protein 5 but it is also inhibited by protein 7, which is activated as a consequence of signal transduction from receptor C. Protein 1, activated by receptor B, is activated by protein 7 but inhibited by protein 6, both of which are activated by receptor C. Clearly, in this hypothetical example, the extent to which the downstream targets of the three pathways become activated will depend, in a very complicated way, on the activities of the proteins in all three pathways, because of crosstalk between the pathways. 

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