Cytosolic hormone receptors

Cytosolic Hormone Receptors. Steroid hormones typically bind to protein receptors, which are located directly within the cytosol (see Fig. 28-2).17 Of course, this means that the hormone must first enter the cell, which is easily accomplished by the steroid hormones because they are highly lipid soluble. After entering the cell, the hormone initiates a series of events that are depicted in Figure 28-3. Basically, the hormone and receptor form a large activated steroid-receptor complex.17 This complex travels to the cell s nucleus, where it binds to specific genes located within the DNA sequence.31,40 This process initiates gene expres-... 

Several hundred volatile isoprenoid substances that interfere with insect larval moulting have so far been resolved from plants and such phytoecdysones will be dealt with in Chapter 11, which is concerned with development-perturbing compounds binding to cytosolic hormone receptors. It must also be noted that plant cells within a plant (and indeed whole plants themselves) can communicate with each other via volatile signalling bioactives... 

The members of the cytosolic hormone receptor family are homologous proteins and the mechanism of action involves translocation of the receptor with hormone bound to the nucleus, where it homodimerizes (or heterodimerizes with related activated receptors) and binds to specific promoters to switch on transcription of particular genes. The ultimate response to the hormonal stimulus is expression of particular proteins that variously influence development and metabolism as briefly outlined below. 

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