Abstracts (poster) - Wissenschaft Online

Lorenz Kallenbach, Patrick Heun
Role of the SUMO E3 ligase PIAS in chromosome and nuclear
organization in Drosophila melanogaster
PIAS proteins were first identified as components of the JAK/STAT signal transduction
pathway. In Drosophila, the only member of the PIAS family, Su(var)2-10, was found to
be a suppressor of position effect variegation (PEV) (Reuter and Wolff, 1981). It is the
only member of the PIAS-protein family in flies. Further studies of dPIAS suggested
diverse roles in chromosome function and nuclear organization (Hari et al., 2001). This
is consistent with the demonstration that PIAS proteins encode an E3 SUMO Ligase,
which is part of the SUMO conjugating system (Heun, 2007). We found that in
Drosophila there are at least 12 PIAS isoforms that result from alternative splicing.
These isoforms share a central core, but differ in their N- and C-termini. Interestingly,
they show different patterns of expression, are present in distinct complexes, and
appear to have different target proteins.
The aim of this project is to determine how dPIAS mediated SUMOylation regulates
heterochromatin formation and nuclear organization. We are currently trying to identify
the dPIAS isoforms involved in PEV and their corresponding target proteins. Then we will
determine the effect of SUMOylation on the function of the target proteins.
Literature
Reuter, G. and I. Wolff, Isolation of dominant suppressor mutations for position effect
variegation in Drosophila melanogaster. Mol Gen Genet, 1981.
Hari, K.L., K.R. Cook, and G.H. Karpen, The Drosophila Su(var)2-10 locus regulates
chromosome structure and function and encodes a member of the PIAS protein family.
Genes Dev, 2001. 15(11): p. 1334-48.
Heun, P., SUMOrganization of the nucleus. Curr Opin Cell Biol, 2007. 19: p. 1-6.
contact:
Lorenz Kallenbach
Max-Planck-Institute of Immunobiology
kallenbach@immunbio.mpg.de
Stuebeweg 51
79106 Freiburg (Germany)