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Showing posts from March, 2006

Clathrin - the super cool cellular transport machine

From the University of Hamburg's website: Clathrin and Coated Vesicles:
Clathrin is a protein with an extraordinary structure. It is a trimer with three leg-like subunits. Its extraordinary structure enables the protein to polymerize in a two-dimensional network consisting of numerous hexagons. Strictly speaking [the aggregate forms not a plane but] a bent surface with a convex and a concave side. It is an open question whether the tendency to bend has intramolecular or intermolecular causes. Especially important is the fact that such networks fit with their concave side tightly to membranes, for example to the inner surface of the plasmalemma. The growing network provides the mechanical force to pull the membrane into a bud. This bud is finally pinched off: a clathrin-coated vesicle has been formed.

Coated vesicles are known to exist in a range of plant and animal cells (E. H. NEWCOMB, 1980). They bring extracellular substances into the cell, a process called endocytosis. Within…