In Dictyostelium discoideum, the Ca2+-ATPase, PAT1, is localized to membranes of the contractile vacuole and its expression is upregulated substantially when the cells are grown in Ca2+-rich medium. In this study, we have analyzed the cellular/molecular mechanisms regulating PAT1 expression and examined the role of PAT1 and the contractile vacuole in Ca2+ regulation. During both growth and deve...

NEO1 is an essential gene in budding yeast and belongs to a highly conserved subfamily of P-type ATPase genes that encode phospholipid flippases. Inactivation of temperature sensitive neo1ts alleles produces pleiomorphic defects in the secretory and endocytic pathways, including fragmented vacuoles. A screen for multicopy suppressors of neo1-2ts growth defects yielded YPT7, which encodes a Rab7...

Plasmodium falciparum Merozoite Surface Protein 1 (MSP1) is synthesized during schizogony as a 195-kDa precursor that is processed into four fragments on the parasite surface. Following a second proteolytic cleavage during merozoite invasion of the red blood cell, most of the protein is shed from the surface except for the C-terminal 19-kDa fragment (MSP1(19)), which is still attached to the me...

To be submitted SUMMARY The lytic vacuole is the main vacuole of the plant cell and is usually indicated as the central vacuole (CV). This compartment occupies up to over 90% of the cell volume and its lumen is more acidic than the surrounding cytoplasm. In the epidermal cells of flower petals the CV specialized to display the color due to anthocyanin pigments accumulation. Here we show that th...

We have used a lipophilic styryl dye, N-(3-triethylammoniumpropyl)-4- (p-diethylaminophenyl-hexatrienyl) pyridinium dibromide (FM 4-64), as a vital stain to follow bulk membrane-internalization and transport to the vacuole in yeast. After treatment for 60 min at 30 degrees C, FM 4-64 stained the vacuole membrane (ring staining pattern). FM 4-64 did not appear to reach the vacuole by passive dif...

The key gluconeogenic enzyme fructose-1,6-bisphosphatase (FBPase) is induced when Saccharomyces cerevisiae are starved of glucose. However, when glucose is added to cells that have been starved for 3 days, FBPase is degraded in the vacuole. FBPase is first imported to Vid (vacuole import and degradation) vesicles, and these vesicles then merge with the endocytic pathway. In this report we show ...

The interaction between v-SNAREs on transport vesicles and t-SNAREs on target membranes is required for membrane traffic in eukaryotic cells. Here we identify Vti1p as the first v-SNARE protein found to be required for biosynthetic traffic into the yeast vacuole, the equivalent of the mammalian lysosome. Certain vti1-ts yeast mutants are defective in alkaline phosphatase transport from the Golg...

Escape from the host erythrocyte by the invasive stage of the malaria parasite Plasmodium falciparum is a fundamental step in the pathogenesis of malaria of which little is known. Upon merozoite invasion of the host cell, the parasite becomes enclosed within a parasitophorous vacuole, the compartment in which the parasite undergoes growth followed by asexual division to produce 16-32 daughter m...

The homotypic fusion of yeast vacuoles occurs in an ordered cascade of priming, docking, and fusion. The linkage between these steps has so far remained unclear. We now report that Vam7p (the vacuolar SNAP-23/25 homolog) signals from the cis-SNARE complex to Ypt7p (the vacuolar Rab/Ypt) to initiate the docking process. After Vam7p has been released from the cis-SNARE complex by Sec18p-mediated ...