Test Your Knowledge on Actin

• Actin is a protein present in all eukaryotic species and is the most abundant protein in the cell (5% of total proteins).
• Actin can polymerize monomers into filaments, which are either stable or labile depending on various conditions.
• The filaments are polarized, with the positive end elongating and the negative end doing the opposite.
• Actin filaments are the thinnest, weakest, and fastest-changing of the cytoskeletal filaments.
• Phalloidin is a toxin that affects actin filaments and is used to visualize actin in fluorescence microscopy.
• Actin has two forms: G (globular) and F (filamentous), with F resulting from the polymerization of G through ATP hydrolysis.
• Actin is an ATPase, meaning it can form ATP and ADP.
• The structure of actin filaments depends on the site of formation, dynamics of polymerization/depolymerization, associated proteins, and myosin presence.
• Actin filaments are involved in cell migration and adhesion.
• The conformational differences between actin bound to ATP or ADP are subtle but can result in allosteric changes.

How much do you know about actin, the most abundant protein in the cell? Test your knowledge with this quiz and learn about its polymerization, filaments, structure, and various functions in cell migration and adhesion. Discover the differences between its G and F forms and the subtle but important allosteric changes caused by ATP or ADP binding. Take the quiz and become an actin expert!