Abstract
We have characterized the morphology of the yeast endocytic pathway leading from the plasma membrane to the vacuole by following the trafficking of positively charged nanogold in combination with compartment identification using immunolocalization of t-SNARE proteins. The first endocytic compartment, termed the early/recycling endosome, contains the t-SNARE, Tlg1p. The next compartment, the prevacuolar compartment, contains Pep12p. After transport to the prevacuolar compartment, where vacuolar enzymes are seen on their way to the vacuole, endocytic content is delivered to the late endosome and on to the vacuole, both of which are devoid of Pep12p immunolabel. Traffic to the prevacuolar compartment is reduced in strains mutant for the Rab5 homologs, Vps21p, Ypt52p, and Ypt53p and in vps27 mutant cells. On the other hand, traffic to the early recycling endosome is less dependent on Rab5 homologs and does not require Vps27p.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Carboxypeptidases / metabolism
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Carrier Proteins / metabolism
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Cathepsin A
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Endocytosis*
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Endosomal Sorting Complexes Required for Transport
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Endosomes / metabolism
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Fungal Proteins / metabolism
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Membrane Proteins / metabolism*
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Microscopy, Electron
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Microscopy, Fluorescence
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Protein Binding
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Qa-SNARE Proteins
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SNARE Proteins
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins*
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Time Factors
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Vesicular Transport Proteins*
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rab GTP-Binding Proteins / metabolism
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rab5 GTP-Binding Proteins / genetics*
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rab5 GTP-Binding Proteins / metabolism
Substances
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Carrier Proteins
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Endosomal Sorting Complexes Required for Transport
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Fungal Proteins
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Membrane Proteins
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PEP12 protein, S cerevisiae
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Qa-SNARE Proteins
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SNARE Proteins
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Saccharomyces cerevisiae Proteins
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VPS27 protein, S cerevisiae
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Vesicular Transport Proteins
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Carboxypeptidases
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Cathepsin A
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rab GTP-Binding Proteins
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rab5 GTP-Binding Proteins