Final answer:
The FtsZ protein is involved in the binary fission of bacteria, assembling into a Z ring at the site of cell division and functioning similarly to tubulin in eukaryotic cells.
Step-by-step explanation:
The cytoskeletal protein expected to be involved in binary fission of a bacterium is the FtsZ protein. This protein is a homolog of tubulin found in eukaryotes and is essential in prokaryotic cell division. FtsZ forms a constriction ring at the site of division, known as a Z ring, which guides the formation of a division septum that eventually leads to the separation of the two new bacterial cells. Unlike tubulin, which has diversified in eukaryotic cells to form complex structures like mitotic spindles, FtsZ retains a more singular function in bacterial cytokinesis.
The FtsZ protein facilitates the copying of DNA and ensures that each daughter cell receives an exact copy of the parent's DNA.