Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2000-2-18
pubmed:abstractText
Hermansky-Pudlak syndrome (HPS) comprises a group of genetic disorders characterized by defective lysosome-related organelles. The most common form of HPS (HPS type 1) is caused by mutations in a gene encoding a protein with no homology to any other known protein. Here we report the identification and biochemical characterization of this gene product, termed HPS1p. Endogenous HPS1p was detected in a wide variety of human cell lines and exhibited an electrophoretic mobility corresponding to a protein of approximately 80 kDa. In contrast to previous theoretical analysis predicting that HPS1p is an integral membrane protein, we found that this protein was predominantly cytosolic, with a small amount being peripherally associated with membranes. The sedimentation coefficient of the soluble form of HPS1p was approximately 6 S as inferred from ultracentrifugation on sucrose gradients. HPS1p-deficient cells derived from patients with HPS type 1 displayed normal distribution and trafficking of the lysosomal membrane proteins, CD63 and Lamp-1. This was in contrast to cells from HPS type 2 patients, having mutations in the beta3A subunit of the AP-3 adaptor complex, which exhibited increased routing of these lysosomal proteins through the plasma membrane. Similar analyses performed on fibroblasts from 10 different mouse models of HPS revealed that only the AP-3 mutants pearl and mocha display increased trafficking of Lamp-1 through the plasma membrane. Taken together, these observations suggest that the product of the HPS1 gene is a cytosolic protein capable of associating with membranes and involved in the biogenesis and/or function of lysosome-related organelles by a mechanism distinct from that dependent on the AP-3 complex.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1300-6
pubmed:dateRevised
2004-11-18
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Molecular characterization of the protein encoded by the Hermansky-Pudlak syndrome type 1 gene.
pubmed:affiliation
Cell Biology and Metabolism Branch, NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA.
pubmed:publicationType
Journal Article