Structure, assembly, and dynamics of actin filaments in situ and in vitro

Actin, though highly conserved, exhibits a myriad of diverse functions, mos t of which ultimately depend on its intrinsic ability to rapidly assemble a nd disassemble filamentous structures. Many organisms synthesize multiple a ctin isoforms even within the same cell. Tissue-specific expression pattern s and tight developmental regulation as well as a high conservation across species emphasize the functional importance of isoforms. The detailed knowl edge of the structure, assembly, and dynamic behavior of actin provides imp ortant pieces in solving the puzzle of how the different isoforms can be so versatile despite their extremely high sequence identity. (C) 1999 Wiley-L iss, Inc.