Types and Tissues

Alterations to the P53 gene are the most common genetic defects known in cancer [5]. The protein product of P53 is involved in a number of pathways that directly and indirectly lead to apoptosis. Many genes that are involved in apoptosis can be induced by this protein, which is a transcriptional transactivator. The emerging hypothesis is that p53 is a central node of a complex apoptotic network that may function differ ently in diver se cell types and tissues. For example, Bax, the prototype proapoptotic member of the Bcl2 family, can be transcriptionally induced by p53 in certain, but not all, cell types. Like p53, Bax can modulate the extent to which cells are sensitive to apoptosis caused by therapeutic agents. 

CNG channels are expressed in retinal photoreceptors and olfactory neurons, and play a key role in visual and olfactory signal transduction. In addition, CNG channels are found at low density in some other cell types and tissues such as brain, testis, and kidney. While the function of CNG channels in sensory neurons has been unequivocally demonstrated, the role of these channels in other cell types, where expression has been observed, remains to be established. Based on their phylogenetic relationship, the six CNG channels... 

Cholesterol is absolutely required by human beings for two reasons. The flrst one we have already noted cholesterol is the starting place for the synthesis of other steroids that are themselves required for normal human physiology. The second reason is that cholesterol is a key constituent of cell membranes in all cell types and tissues of the body. 

The more subtle roles of different PMCAs in cardiac and sperm function, synaptic signaling in retina and hippocampus, etc. suggest that these are not housekeeping genes, rather they provide an important function in many cell types and tissues. It seems likely that changes in each of the PMCA isoforms may contribute quantitatively to a number of complex diseases in ways yet to be discovered. 

The mammalian PPAR family also includes a third isoform, referred to as PPAR8 (22), which is also known as PPAR(3 or NUC1 and is expressed in many different cell types and tissues (13, 22). Specific target genes, natural ligands, and bona fide physiologic roles for PPARS remain to be defined. 

Name Cell type and tissue origin Morphology... 

The effect of altered thyroid state on the activity of the /3-adrenergic receptor-adenylate cyclase complex have been documented in a number of cell types and tissues such as turkey erytrhrocytes, marrow cells, salivary glands, pancreatic cells, isolated hepatocytes, cardiac membranes and adipocytes. However changes in f3-adrenergic responsiveness do not occur in all cell types. 

Page 107, figure 11.8b J. Biol. Chem. 277 9637-9640 (2002), Gow A.J. et ah Basal and stimulated protein S-ni-trosylation in multiple cell types and tissues. 

The seven mammahan coronins exhibit a distinct pattern of expression across cell types and tissues. The best-characterized CRN4/CORO 1A is virtually exclusively expressed in thymocytes, T-cells, macrophages and ncutrophils. It has been shown to function in actin-dependent processes as well as in specific functions unrelated to actin. For a detailed view on mammahan CORO 1A regarding its interaction with actin please refer to Chapters 5 and 6 and to Chapter 11,5th section, for details regarding actin-unrelated functions please refer to Chapter 10 and also Chapter 11,5 th section. 

Even more attractive, yet more difficult to achieve, therapeutic potentials for RNAi are being explored very aggressively by many industrial and academic groups. At this point, the key challenge is in developing reliable and physiological cell type and tissue-specific delivery protocols. If this task is accomplished, the potential for the RNAi will be truly astounding. 

---