TWA1 is a 228 amino acid nuclear protein that is highly conserved throughout evolution. TWA1 interacts with Ran BP-M, a protein that is implicated in a diverse array of cellular processes including DNA replication, entry into and exit from mitosis, and the transport of RNA and proteins through the nuclear pore complex. Together, Ran BP-M and TWA1 form a complex with cytoplasmic Muskelin, a mediator of cell spreading. It is thought that this complex plays a role in the Ran GTPase cycle and therefore a potential role in the cell cycle. TWA1 contains a LisH-CTLH motif which is usually found in proteins that are involved in nucleokinesis, chromosome segregation, cell migration and microtubule dynamics. The gene encoding TWA1 maps to human chromosome 20, which comprises approximately 2% of the human genome and contains nearly 63 million bases that encode over 600 genes.