Figure 3.

SILAC identification of preponderant putative BLOC-1 interactors. A, B depict 43 specific polypeptides specified in Table 2 that associate with FLAG-dysbindin after subtraction with the nonspecific polypeptide library obtained from cross-linked nontransfected SH-SY5Y and HEK293 cells. Gray lines depict the twofold enrichment cutoff. Red symbols denote proteins identified from SH-SY5Y cells expressing FLAG-dysbindin, and blue symbols denote FLAG-muted. Note that dysbindin and the AP-3 subunit AP-3 β3A are similarly enriched and represented by a similar number of peptides. In B, protein number corresponds to the entry number in Table 2. C shows that 24 proteins exclusively and reproducibly identified as preponderant BLOC-1 interactors assemble in four protein complexes. Other than subunits of the adaptor protein AP-3, members of the BLOC-1 complex, and clathrin 17 (CHC17), other proteins listed here are novel BLOC-1 interactors. The table depicts the maximal fold enrichment for any polypeptide in three independent SILAC experiments and the sum of polypeptides correspond to all polypeptides identified in three SILAC and one non-SILAC MS/MS experiment.