Signaling pathway crosstalk

A number of proteins that inhibit the JAK-STAT function have also been identified. These include members of the so-called SOCS/Jab/Cis family and the PIAS family of regulatory proteins. Several appear to function by inhibiting the activation of various STATs, although the mechanisms by which this is achieved remain to be elucidated in detail. The JAK-STAT pathway likely does not function in isolation within the cell. JAKs are believed to activate elements of additional signalling pathways, and STATs are also likely activated by factors other than JAKs. As such, there may be considerable crosstalk between various JAK- and/or STAT-dependent signalling pathways. 

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. " ... 

Phytohormones such as ethylene, salicylic acid (SA), JA, and abscisic acid (ABA) regulate responses of plants to stresses via action referred as signaling crosstalk. Moreover, reactive oxygen species (ROS), the toxic byproducts of aerobic metabolism, play the important role of signaling molecules. Usually, the defensive responses of plants depend on the interaction (positive or negative) between phytohormone signaling pathways rather than on the independent contribution of each of them. " ... 

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 ethiology of chronic inflammatory diseases differs from acute inflammation and is still poorly understood. One example is the chronic rheumatoid arthritis (RA), which is characterized by a chronic destructive arthropathy. In RA and other inflammatory bone diseases there is intense crosstalk between the skeleton and the immune system by the use of common cytokines and transcriptional pathways. A newly established research area - osteoimmunology - attempts to unravel this skeletal/immunological axis and several signaling pathways involved in inflammatory bone loss have been identified (Wagner and Eferl, 2005). One pathway... 

The TG F/ /Smad signaling pathway is controlled at various levels and is subjected to crosstalk with other signaling pathways (Fig. 12.2). The main regulatory influences are listed below (review Kloos et al., 2002). 

Table 4 AHR crosstalk with other signaling pathways...

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