IDENTIFICATION OF KLHDC5 AS AN INTERACTING PROTEIN OF STARD7

ROJAS ML; FLORES MARTIN J; PANZETTA-DUTARI GM; GENTI-RAIMONDI SUSANA

Córdoba

Congreso; 52 th Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2016

SAIB

StarD7 belongs to the steroidogenic acute regulatory protein-related lipid transfer domain proteins that transfer phospholipids among intracellular membranes. It facilitates the delivery of phosphatidylcholine to the mitochondria and previous results indicated that StarD7 knockdown decreases ABCG2 multidrug transporter level, cell migration, proliferation, and phospholipid synthesis. The purpose of this study was the identification of candidate proteins that interact with StarD7. Using peptide LC-mass spectrometry, we identified KLDHC5, a substrate-specific adapter of a BCR(BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex required for mitotic progression and cytokinesis, as a novel protein that interacts with StarD7. The association between the two proteins was confirmed by coinmunoprecipitation and immunofluorescence staining. Cytoplasmic colocalization of both proteins was demonstrated in stable StarD7 HEK293T cells transiently transfected with KLHDC5. Interestingly, HEK293T cells overexpressing StarD7 resulted in an increased number of cells with persistent microtubule bridges between post-mitotic cells as well as multinucleated cells. Taken together these results suggest that StarD7 may participate with KLHDC5 in a protein complex regulating the mitotic division through the localization of lipids required for this process.