The protein “missing in metastasis”, known as MIM, has been characterised as an actin-binding scaffold protein that may be involved in cancer metastasis. In this paper, we summarise the literature surrounding the role of MIM in actin and membrane dynamics and in signalling to transcription via the sonic hedgehog pathway. MIM is postulated to have many potential activities, including a BAR-like domain termed the IMD (IRS-MIM domain), which can interact with membranes to induce membrane deformation and also with actin and the small GTPase Rac. How this multifunctional protein and its close relative ABBA-1 regulate cellular behaviour is still very much an open question.