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How to make a lysosome

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Coated vesicles had been described as early as 1961... These small membranous structures were characterized by a highly organized layer of material on the cytoplasmic surface, “but no one knew their function,” says Marilyn Farquhar, whose lab at the time had become interested in how the Golgi complex helped produce enzymes... Roth and Porter (1964) had provided evidence that coated vesicles have specialized functions in the cellular uptake of proteins... But for Friend and Farquhar (1967), the simple idea of uptake was not enough... The two pathways converged in multivesicular bodies (now known as endosomes), explaining how proteins could be endocytosed and then processed by cellular enzymes... The processing, we now know, takes places only after endosomes have either matured into or sent vesicles to lysosomes... The 1967 paper “was quite unique for its time,” says Farquhar, because the group used three labels: soluble horseradish peroxidase as a tracer for protein uptake; thiamine pyrophosphatase as a Golgi marker; and acid phosphatase as a lysosomal enzyme marker... One type of coated vesicle, which was larger in diameter, formed at the cell surface by pinocytic invagination of the apical cell membrane... It moved toward and fused with multivesicular bodies, thereby serving to transport endocytosed protein inside the cell... The other type of coated vesicle, smaller in size, seemed to originate from the Golgi cisternae and serve, at least in part, to transport the enzyme acid phosphatase and possibly other acid hydrolases from their site of packaging in the Golgi to multivesicular bodies, thus uniting the endocytosed and lytic proteins... Since the small vesicles, which Farquhar refers to as “Golgi vesicles,” carry lytic enzymes, the authors concluded they correspond to primary lysosomes—particles that contain hydrolytic enzymes but have not yet participated in digestion.

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Vesicles large (lv) and small (sv) deliver contents to the incipient lysosome.FARQUHAR
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uro1: Vesicles large (lv) and small (sv) deliver contents to the incipient lysosome.FARQUHAR


How to make a lysosome
Vesicles large (lv) and small (sv) deliver contents to the incipient lysosome.FARQUHAR
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2254812&req=5

uro1: Vesicles large (lv) and small (sv) deliver contents to the incipient lysosome.FARQUHAR

View Article: PubMed Central

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Coated vesicles had been described as early as 1961... These small membranous structures were characterized by a highly organized layer of material on the cytoplasmic surface, “but no one knew their function,” says Marilyn Farquhar, whose lab at the time had become interested in how the Golgi complex helped produce enzymes... Roth and Porter (1964) had provided evidence that coated vesicles have specialized functions in the cellular uptake of proteins... But for Friend and Farquhar (1967), the simple idea of uptake was not enough... The two pathways converged in multivesicular bodies (now known as endosomes), explaining how proteins could be endocytosed and then processed by cellular enzymes... The processing, we now know, takes places only after endosomes have either matured into or sent vesicles to lysosomes... The 1967 paper “was quite unique for its time,” says Farquhar, because the group used three labels: soluble horseradish peroxidase as a tracer for protein uptake; thiamine pyrophosphatase as a Golgi marker; and acid phosphatase as a lysosomal enzyme marker... One type of coated vesicle, which was larger in diameter, formed at the cell surface by pinocytic invagination of the apical cell membrane... It moved toward and fused with multivesicular bodies, thereby serving to transport endocytosed protein inside the cell... The other type of coated vesicle, smaller in size, seemed to originate from the Golgi cisternae and serve, at least in part, to transport the enzyme acid phosphatase and possibly other acid hydrolases from their site of packaging in the Golgi to multivesicular bodies, thus uniting the endocytosed and lytic proteins... Since the small vesicles, which Farquhar refers to as “Golgi vesicles,” carry lytic enzymes, the authors concluded they correspond to primary lysosomes—particles that contain hydrolytic enzymes but have not yet participated in digestion.

No MeSH data available.


Related in: MedlinePlus