Functional interaction between LITAF and LTCC in tsA201 cells. Cells were transfected with plasmids for Cavα1c, Cavβ3, and Cavα2δ−1 to reconstitute functional LTCC, GFP, or HA-tagged LITAF. Cell-surface protein levels were determined by biotinylation: cell-surface proteins were biotinylated using sulfo-NHS-SS-biotin, purified with neutravidin beads from total cell lysates, subjected to SDS-PAGE and blotted onto a nitrocellulose membrane. A, A representative western blot shows total protein levels of Cavα1c, Cavβ3, Cavα2δ−1, HA-LITAF, and tubulin (left panel). Respective change in total Cavα1c abundance, normalized to tubulin levels (n=5, performed in triplicate; mean±SEM). Student’s t-test, p<0.05 (right panel). B, A representative western blot shows cell surface protein levels of Cavα1c, Cavβ3, Cavα2δ−1, transferrin receptor (TFR), total LITAF, and HA-LITAF (left panel). Respective changes in cell membrane protein levels of Cavα1c, Cavβ3, and Cavα2δ−1 normalized to transferrin receptor levels (n=5, performed in triplicate; mean±SEM). Student’s t-test, p<0.05 (right panel).