L Top: GSTpull‐down assay of wild‐type or 6RQ mutant of LAPTM4B N‐terminus and PIPKIγi5 C‐terminus with 0.5 μM addition of PtdIns(4,5) P2. Bottom: Quantification of the relative amounts of PIPKIγi5 C‐terminus bound to LAPTM4B N‐terminus in top panel (mean + SD; n = 4). 