Figure 2.

BAIAP3 is required for spontaneous DCV exocytosis. (A) Possible secretion pathways for NPY-Venus release: spontaneous DCV exocytosis at resting condition or stimulated exocytosis during stimulation. (B) Ca²⁺-triggered secretion of PC1. (C) NPY-Venus and PC1 in cell lysates and conditioned culture medium after 2 d. (D) Liquid chromatography tandem mass spectrometry analysis of spontaneously secreted proteins and acutely secreted proteins. Proteins are quantified by label-free quantification and ranked by their abundance in culture medium. n = 3 for each condition. (E) Spontaneous NPY-Venus secretion into culture medium from wild-type, BAIAP3 knockdown, or CAPS knockdown cells. n = 3. (B, C, and E) Molecular mass is shown in kilodaltons. (F) Quantification of NPY-Venus in cell lysates, culture medium, or total (culture medium + cell lysate) for conditions similar to E after normalizing to cell number. n = 3 independent experiments. See also Fig. S2. Data are expressed as mean ± SD. P-values were obtained by a two-tailed Student’s t test. *, P < 0.05; **, P < 0.01. KD, knockdown; NT, nontargeting.