First Author | Bernstein AM | Year | 1999 |
Journal | Blood | Volume | 93 |
Issue | 2 | Pages | 571-9 |
PubMed ID | 9885218 | Mgi Jnum | J:52066 |
Mgi Id | MGI:1327767 | Doi | 10.1182/blood.v93.2.571.402k05_571_579 |
Citation | Bernstein AM, et al. (1999) Identification of a cellubrevin/vesicle associated membrane protein 3 homologue in human platelets. Blood 93(2):571-9 |
abstractText | Several studies suggest membrane trafficking events are mediated by integral, membrane proteins from both transport-vesicle and target membranes, called v- and t-SNAREs (SNAp REceptors), respectively. Previous experiments using antibodies to synaptobrevin/vesicle associated membrane protein (VAMP) 1, 2, or rat cellubrevin failed to detect these v-SNAREs in human platelets, although membrane proteins from these cells could support 20S complex formation. To identify v-SNAREs in platelets, we used a polymerase chain reaction (PCR) approach with degenerate primers to amplify potential VAMP-like v-SNAREs. A cDNA encoding a novel v-SNARE was isolated from a human megakaryocyte cDNA library. Termed human cellubrevin (Hceb), this protein has greater than 93% identity with human VAMP 1, 2, and rat cellubrevin over the conserved core region, but has a unique N-terminal domain. Northern blot analysis showed that the 2. 5-kB mRNA encoding Hceb is expressed in every human tissue tested. Hceb from detergent-solubilized platelet membranes, participated in alpha-SNAP-dependent 20S complex formation and adenosine triphosphate (ATP)-dependent disassembly, showing that Hceb can act as a v-SNARE in platelets. Immunofluorescence microscopy, using an anti-Hceb antibody showed a punctate, intracellular staining pattern in platelets, megakaryocytes, and HEK-293 cells. This same pattern was observed in surface-activated platelets even though all dense core and most alpha-granule contents had been released. These data suggest that Hceb may reside on a platelet organelle that is not primarily involved in the exocytic pathway. |