Question

The following proteins are important for cell movement. Match the following proteins with their function.

1) nucleation of new actin filaments at the side of an existing filament
2) regulation of the availability of actin monomers
3) important for the growth of straight, unbranched actin filaments
4) contracting the rear of the cell
5) involvement in focal contacts

Answer 1

In cell movement, proteins such as the Arp2/3 complex, profilin, formins, myosin II, and integrins have distinct functions ranging from actin filament nucleation and elongation to providing contractile forces and establishing cell-matrix interactions.

Step-by-step explanation:

The proteins involved in cell movement correspond to the following functions:

1. Nucleation of new actin filaments at the side of an existing filament is typically associated with the Arp2/3 complex, which initiates the growth of branched actin networks necessary for cellular protrusions.
2. Regulation of the availability of actin monomers is managed by proteins like profilin, which helps maintain a pool of actin monomers that can be added to the growing end of a filament.
3. Filamentous actin (F-actin) growth of straight, unbranched actin filaments is promoted by formins, which nucleate and elongate unbranched actin chains.
4. Contracting the rear of the cell is the role of myosin II, a motor protein that works in conjunction with actin filaments to generate contractile forces.
5. Involvement in focal contacts is a feature of integrins, which are transmembrane receptors that link the actin cytoskeleton with the extracellular matrix, thus helping the cell to adhere to its surroundings.

Each of these proteins plays a specific role in the complex process of cellular movement and structure, from actin filament dynamics to interactions with the extracellular matrix.