INVESTIGADORES
CECCARELLI Eduardo Augusto
congresos y reuniones científicas
Título:
ClpS: a Novel Substrate Selector of the Clp System in Arabidopsis thaliana
Autor/es:
COLOMBO, C. V.; ROSANO, G. L.; MOGK, A; CECCARELLI, E. A.
Lugar:
Buenos Aires
Reunión:
Congreso; XLIX Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2013
Institución organizadora:
Sociedad Argentina de Investigación Bioquímica y Biología Molecular
Resumen:
Proteolysis is an essential mechanism in protein quality control. In
chloroplasts, this function is accomplished by the ClpPR complex,
which acts as a protein-degradation machine. The chaperones ClpC1/
2 and ClpD select and unfold substrate proteins and translocate
them to ClpPR. However, target selection appears to be aided by
adaptor proteins that bind to the chaperones. For example, ClpS is
proposed to modulate ClpC1/2 substrate selection and affinity, yet
its function is unknown. Interestingly, ClpS from Escherichia coli
is the discriminator of the N-end rule pathway. The rule states that
the half-life of a protein is determined by the nature of its aminoterminal
residue. E. coli ClpS recognizes N-end rule substrates and
presents them to the ClpAP protease. Based on these observations
from bacteria and the fact that ClpS is present in plants, the existence
of the N-end rule pathway in chloroplast is possible. Using
recombinant ClpS from Arabidopsis thaliana, we found by gel
filtration chromatography that it can form homo-oligomers of 2, 3,
4 and 6 subunits. ClpS was found to interact with ClpC2 and
ClpD, which is in line with its proposed biological function.
Importantly, ClpS was able to bind substrates recognized by E.
coli ClpS. Our results suggest that ClpS plays a role in substrate
selection for the Clp system in plants, maybe following the rules of
the N-end pathway.