Cytoskeleton is a dynamic network of proteins, which are required by all cells for cell division, growth and maintenance of cell shape. A major group of cytoskeleton proteins present in nearly all cells are the tubulin superfamily. Archaea, the third domain of life, are microbes known for their capability to thrive in harsh environments, and encode a great diversity of tubulin superfamily proteins including FtsZ, and tubulins more similar to those in eukaryotes. Our group has recently found that a new cytoskeletal protein family in archaea, named “CetZ”, are involved in cell shape regulation. They form dynamic cytoplasmic filaments at or near the cell envelope, that are required for cell shape determination. The mechanism by which CetZ proteins lead to remodelling of the cell envelope to modulate cell shape is unknown. Based on crystal structures of CetZ proteins and their likely manner of self-association, we have initiated a structure-function analysis of CetZ interactions and functions in vitro and in vivo. Point mutants were introduced into the Haloferax volcanii CetZ1 protein, designed to target putative functional interactions in self-association and putative membrane association. Light scattering and TEM were used as an approach to analyse the polymerization cycle and structural features of CetZ polymers, correlating these to the in vivo structures observed by high- and super-resolution fluorescence microscopy. Understanding tubulin-like cytoskeleton proteins in archaea are expected to provide insights into cytoskeleton evolution and help reveal fundamental principles of cytoskeletal function across the three domains of life.