This entry represents a small family of single-pass membrane proteins described as small integral membrane proteins, including SMIM5/18/22 which have been described as variants of the Cancer-Associated Small Integral Membrane Open reading frame 1 (CASIMO1), a small open reading frame (sORF)-encode protein. CASIMO1 controls cell proliferation and interacts with squalene epoxidase (SQLE) modulating lipid droplet formation. CASIMO1 RNA is overexpressed predominantly in hormone receptor-positive breast tumors. Loss of CASIMO1 disturbs the organisation of the actin cytoskeleton, leads to inhibitions of cell motility, and stalls the cell cycle in the G0/G1 phase [1].

1: The cancer-associated microprotein CASIMO1 controls cell proliferation and\tinteracts with squalene epoxidase modulating lipid droplet formation. Polycarpou-Schwarz M, Gross M, Mestdagh P, Schott J, Grund SE, Hildenbrand C, Rom J, Aulmann S, Sinn HP, Vandesompele J, Diederichs S; Oncogene. 2018;37:4750-4768. PMID:29765154