We have investigated the possibility that vacuolar proteins can be secreted into the medium of cultured cells of @entity286 . Time-course and balance-sheet experiments showed that a large fraction, up to ca. 19%, of vacuolar alpha-mannosidase (EC 3.2.1.24) and vacuolar class I chitinase (EC 3.2.1.14) in suspension cultures accumulated in the medium within one week after subculturing. This effect was most pronounced in media containing @entity14462 ( @entity14462 ). Under comparable conditions only a small fraction, 1.8-5.1% of the total protein and ca. 1% of @entity5910 dehydrogenase (EC 1.1.1.37), which is localized primarily in the mitochondria and cytoplasm, accumulated in the medium. Pulse-chase experiments showed that newly synthesized vacuolar class I isoforms of chitinase and beta-1,3-glucanase (EC 3.2.1.39) were released into the medium. Post-translational processing, but not the release of these proteins, was delayed by the secretion inhibitor @entity10613 . Only forms of the proteins present in the vacuole, i.e. mature chitinase and pro-beta-1,3-glucanase and mature beta-1,3-glucanase, were chased into the medium of @entity286 cell-suspension cultures. Our results provide strong evidence that vacuolar alpha-mannosidase, chitinase and beta-1,3-glucanase can be secreted into the medium. They also suggest that secretion of chitinase and beta-1,3-glucanase might be via a novel pathway in which the proteins pass through the vacuolar compartment.

Evidence for secretion of vacuolar alpha-mannosidase, class I chitinase, and class I beta-1,3-glucanase in suspension cultures of XXXX cells.

@entity10613 :: ('MESH:D020126', 'Chemical') :: ['brefeldin A'] @entity286 :: ('4097', 'Species') :: ['Nicotiana tabacum L', 'tobacco'] @entity14462 :: ('MESH:D015084', 'Chemical') :: ['2,4-dichlorophenoxyacetic acid', '2,4-D'] @entity5910 :: ('MESH:C030298', 'Chemical') :: ['malate']
@entity286 :: (4097,Species) :: ['tobacco']
