CRAL-TRIO domain

CRAL-TRIO domain is a protein structural domain that binds small lipophilic molecules. This domain is named after cellular retinaldehyde-binding protein (CRALBP) and TRIO guanine exchange factor.

CRALB protein carries 11-cis-retinol or 11-cis-retinaldehyde. It modulates interaction of retinoids with visual cycle enzymes. TRIO is involved in coordinating actin remodeling, which is necessary for cell migration and growth.

Other members of the family are alpha-tocopherol transfer protein and phosphatidylinositol-transfer protein (Sec14). They transport their substrates (alpha-tocopherol and phosphatidylinositol or phosphatidylcholine, respectively) between different intracellular membranes. Family also include a guanine nucleotide exchange factor that may function as an effector of RAC1 small G-protein.