DISCOVERY OF A NEW CELLULAR STRUCTURE - POROSOME
(a review)
M. G. Zhvania, I. L. Lazrishvili (Lazriev)
I. Bcritashvili Institute of Physiology, Georgian Academy of Sciences, Tbilisi, Georgia
A new cell structure - "porosome", discovered by the American scientist Bhanu Jena and co-wokers, is described.
Mechanisms of budding and fusion of transport vesicle are elucidated in addition to those of fusion of secretory vesicles at the cell
plasma membrane, and of release of intravesicular contents. The morphology of po-rosomes, their contents and functional reconstruction in
lipid bilayer membranes were examined at a near nanometer resolution. Using atomic force microscopy, the presence of circular "pits",
measuring 400-1200 nm in diameter with small 100-150 nm wide "depressions" inside and 3-4 deep pores, called porosomes, was demonstrated.
A porosome is cup-shaped and 15-30 nm wide. Porosomes are the places where secretory vesicles fuse with the plasma cell membrane, and
where the intravesicular content is released.
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