Paramecium - Deutsche Gesellschaft für Protozoologie / German ...

Functional analysis of Phosphatidyl-Inositol specific Phospholipases
(PI-PLCs) in Paramecium tetraurelia
Christine Klöppel, Jonathan Creutz, Helmut Schmidt, Martin Simon
University of Kaiserslautern
PI-PLCs may have different functions in a cell: as they may accept
either PI (Phosphatidylinositol) or GPI (Glycosly-Phosphatidylinositol)
their involvement concerns quite different metabolic pathways.
We show here the functional splitting of six different PI-PLCs
between extracellular hydrolysis of GPI-anchors but also in
intracellular modes of operation.
GPI-cleavage during antigenic variation but also the artificial cleavage
of these anchors during salt/ethanol extraction was shown the
role for one group of PLCs.
Moreover, T-maze assays show the involvement of two PI-PLCs in
the signal transduction pathway in response to extracellular folate and
interestingly other PI-PLCs are shown to release IP3 (inositol-3phosphate)
in the control mechanism of osmoregulation. Sequence
analysis and comparison of the catalytic domains suggests that this
kind of functional splitting is achieved by different intra- (and extra-)
cellular locations of the specific enzymes.
kloeppel@rhrk.uni-kl.de
mister_wu73@web.de
hjschm@rhrk.uni-kl.de
msimon@rhrk.uni-kl.de
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