Cleavage Products in Signal Transduction

Clycosyl-phosphatidylinositol Cleavage Products in Signal Transduction 

Another open issue in GPI hydrolysis by phospholipases is how intracellular receptor activation couples to the hydrolysis of an extracellular plasma membrane lipid. There are many hypotheses that have not been fully explored, some of which have an experimental basis - for example, there are evidences of fhe presence of both free-GPI and GPI-PLD in intracellular vesicles [27, 30]. Alfhough intracellular GPI-PLD has not been reported to hydrolyse GPI, an intracellular re- 

In summary, there has been a considerable advance in the knowledge of the nature of the specific phospholipases involved in GPI hydrolysis and the mechanism by which these enzymes are regulated and may couple to different receptors. But still many essential aspects of GPI-PLs structure, localization and function have to be elucidated. 

Insulin-stimulated GPI hydrolysis is strictly dependent on the tyrosine kinase activity of the insulin receptor. The lack of tyrosine kinase activity in the insulin recep- 

Abbreviations ACTH, adrenocorticotropic hormone BDNF. brain-derived neurotrophic factop I GI epidermal growth factop Epo, erythropoietin I SII follicle-stimulating hormone IGI -I insulin-like growth factor-I IL. interleukin NGF, nerve growth factop NT-3, neurotrophin-3 IGI -/fl Transforming growth factor-jSl ft 11 thyrotropin releasing hormone I SI I thyrotropin. Blockade of interleu-kin-2-dependent GPI hydrolysis. 

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I 6 ClycosYt-phosphatidylinositol Cleavage Products in Signal Transduction... 

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