Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 2003 Jul 22;100(15):8770-5. Epub 2003 Jul 7.

Biogenesis of lysosome-related organelles complex 3 (BLOC-3): a complex containing the Hermansky-Pudlak syndrome (HPS) proteins HPS1 and HPS4.

Author information

  • 1Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.

Abstract

Hermansky-Pudlak syndrome (HPS) defines a group of autosomal recessive disorders characterized by deficiencies in lysosome-related organelles such as melanosomes and platelet-dense granules. Several HPS genes encode proteins of unknown function including HPS1, HPS3, and HPS4. Here we have identified and characterized endogenous HPS3 and HPS4 proteins from HeLa cells. Both proteins were found in soluble and membrane-associated forms. Sedimentation-velocity and coimmunoprecipitation experiments revealed that HPS4 but not HPS3 associates with HPS1 in a complex, which we term biogenesis of lysosome-related organelles complex 3 (BLOC-3). Mutant fibroblasts deficient in either HPS1 or HPS4 displayed abnormal localization of lysosomes and late endosomes, which were less concentrated at the juxtanuclear region in mutant cells than in control fibroblasts. The coat-color phenotype of young homozygous double-mutant mice deficient in subunits of BLOC-3 (HPS1) and BLOC-1 (pallidin) was indistinguishable from that of BLOC-1 single mutants. Taken together, these observations suggest that HPS1 and HPS4 are components of a protein complex that regulates the intracellular localization of lysosomes and late endosomes and may function in a BLOC-1-dependent pathway for melanosome biogenesis.

PMID:
12847290
[PubMed - indexed for MEDLINE]
PMCID:
PMC166388
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk