Analysis of phosphoinositides in protein trafficking

Phosphoinositides are key regulators of vesicle-mediated protein traffickin g Their roles include recruiting vesicle coat and effector proteins to the site of budding and promoting vesicle fusion. The intracellular levels of p hosphoinositides and their localization to intracellular membranes are crit ical to their functions. An analytical procedure was developed that optimiz es the recovery of radiolabeled cellular phosphoinositides. Quantitative an alyses of yeast cellular phosphoinositides indicated that this approach is useful for examining the intracellular membrane phosphoinositide compositio ns related to trafficking phenomena. The approach will also enable investig ators to determine whole-plant phosphoinositide compositions that have been difficult to achieve in the past. These analytical advances should be gene rally applicable to studies of phosphoinositide dynamics related to membran e trafficking in yeast, plant, and animal cells. (C) 2000 Academic Press.