ARHGAP1 and neoplasm: STARD8 is also involved in the growth and metastasis of tumor cells [59] as are DLC1 and DLC2. Structurally, this protein is composed of three protein domains: a sterile α-motif, a RhoGAP (Rho GTPase-activating protein) domain, and a START domain (StAR, steroidogenic acute regulatory protein, related lipid transfer).