 While most profilin in the cell is bound to actin, profilins have over 50 different binding partners.Many of those are related to actin regulation, but profilin also seems to be involved in activities in the nucleus such as mRNA splicing.Profilin binds some variants of membrane phospholipids (phosphatidylinositol (4,5)-bisphosphate and inositol trisphosphate).