Characterisation of the actin-binding protein Insertin
Insertin is an actin-binding protein which copurifies with vinculin from chicken gizzard. It binds to the barbed ends of actin filaments thereby modulating the polymerisation rate. In contrast to other barbed-end proteins (“capping proteins”) insertin does not fully suppress the polymerisation, but retards it maximally to one fifth of the normal rate of polymerisation. Thus, insertin is able to permit actin polymerisation while bound to the filament ends and is therefore a good candidate for fine tuning actin polymerisation. Localisation of insertin in focal adhesion plaques (dynamic cell-substrate contacts of migrating cells) underlines this potenial role and raises the question of possible interactions with other focal adhesion proteins.
KeywordsArginine Trypsin Barb eDNA
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