MPHOSPH8 is a 860 amino acid nuclear protein that is phosphorylated in the M (mitotic) phase of the cell cycle. MPHOSPH8 contains four ANK repeats, motifs that are typically found in transcriptional regulators and cell cycle proteins and may be involved in protein-protein binding. Due to evidence suggesting that MPHOSPH8 forms a complex with Muskelin and Ran BP-M, a GTPase implicated in a diverse array of cellular processes, it may play a role in the Ran GTPase cycle. The gene encoding MPHOSPH8 resides on chromosome 13. There are two isoforms of MPHOSPH8 that are produced as a result of alternative splicing events.