Figure 5.

PATL1 binds phosphoinositides. Vesicle cosedimentation assays were used to test PATL1 protein for phospholipid-binding activity. A, PATL1 (2.5 μg) was mixed with unilamellar vesicles composed of 25 mm PtdEth, PtdCh, or PtdIns. Vesicle bound proteins (P) were separated from unbound proteins (S) by centrifugation at 164,000g and analyzed by fluorescence scanning of SYPRO red-stained SDS gels. PATL1 protein alone was used as a blank. B, PATL1 binding to phosphoinositides was tested as described above except that unilamellar vesicles were made from a mixture of 10:1 PtdEth:test phosphoinositide and the lipid concentration was 2.2 mm. The percentage of patellin bound was quantified using ImageQuant software. Values are the mean ± se from at least three different experiments.