T-Rex-293 (Invitrogen), IMCD3 Flp-In (IMCD3; American Type Culture Collection; gift of Peter Jackson), Phoenix A (PhA; Indiana University National Gene Vector Biorepository), and 293FT cells were cultured in DMEM high glucose (Sigma-Aldrich; supplemented with 10% cosmic serum, 0.05 mg/ml penicillin, 0.05 mg/ml streptomycin, and 4.5 mM glutamine). NIH 3T3 Flp-In (Thermo Fisher) cells were cultured in DMEM high glucose media (D5796; Sigma) with 10% Bovine calf serum (BCS; Sigma-Aldrich), 0.05 mg/ml penicillin, 0.05 mg/ml streptomycin, and 4.5 mM glutamine. 3T3-L1 cells (gift of Peter Michaely, UTSW) were cultured in DMEM high glucose (Sigma-Aldrich) media with 10% fetal bovine serum, 0.05 mg/ml penicillin, 0.05 mg/ml streptomycin, 4.5 mM glutamine, and 8 ng/ml biotin. Cell lines were tested negative for Mycoplasma using the Mycoplasma PCR Detection Kit (Genlantis). Transfection of plasmids was done with Polyfect (QIAGEN) or polyethylenimine (PEI) max. Stable cell lines were generated by retroviral infection or transfection. In many cases, stable lines were flow sorted and further selected for GFP. Control and Tulp3 ko MEFs were from embryonic day 13.5 embryos (Legue and Liem, 2019 (link)). Immortalized WT and Arl13b mutant MEFs were gifts from Tamara Caspary (Larkins et al., 2011 (link); Gigante et al., 2020 (link)).