Biogenesis Of Lysosomal Organelles Complex 1, Subunit 3 (BLOC1S3)

BLOC1S3 is a component of the ubiquitously expressed BLOC1 multisubunit protein complex. BLOC1 is required for normal biogenesis of specialized organelles of the endosomal-lysosomal system, such as melanosomes and platelet dense granules. The deduced BLOS3 protein has a calculated molecular mass of 21.3 kD. However, Western blot analysis detected endogenous HeLa cell BLOS3 at an apparent molecular mass of 32 kD.Other BLOC1 subunits identified were pallidin, muted, dysbindin (DTNBP1), cappuccino, snapin (SNAPAP), BLOC1S1, and BLOC1S2. Coimmunoprecipitation and yeast 2-hybrid analyses confirmed that these proteins interact within the BLOC1 complex.