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doi: 10.1242/10.1242/jcs.00307
Research Article |
Laboratoire de Bioénergétique et Microbiologie, Université de Genève, 3 Place de l'Université, CH-1211 Genève 4, Switzerland
* Author for correspondence (e-mail: Mukti.Ojha{at}bota.unige.ch)
Accepted 5 December 2002
Immunogold labeling of calcium-dependent neutral protease II (CDPII) with
specific antibodies in near median longitudinal ultrathin sections of
Allomyces arbuscula showed that the enzyme is predominantly localized
in the growing hyphal and rhizoidal apices. The tips in both cell type had
more enzyme than the distal regions and showed a gradient distribution.
Labeling of the ultrathin sections and western blot analysis of purified
subcellular fractions showed that CDPII is mainly cytosolic. Catalytic
activity of the enzyme measured with synthetic substrate (Bz-Arg-pNA) showed
that 90% of its activity is present in the soluble fraction, although a small
amount is associated with the nuclei (0.2%), plasma membranes (0.7%) and
microsomes (3.9%). This association is discussed in the context of the
functional role of the enzyme and its possible localized activation. Western
blot analysis of the crude extract and indirect immunofluorescence of the
fixed permeabilized hypahe after treatment with CDPII showed that the
-tubulin is a specific target of the enzyme.
Key words: Allomyces arbuscula, Calcium-dependent neutral protease, Immunogold labeling, Intracellular localization, Hyphal tips,
-tubulin a specific target