IAL   21557
INSTITUTO DE AGROBIOTECNOLOGIA DEL LITORAL
Unidad Ejecutora - UE
artículos
Título:
Lack of cytochrome c in Arabidopsis decreases stability of Complex IV and modifies redox metabolism without affecting Complexes I and III
Autor/es:
WELCHEN, ELINA; HILDEBRANDT, TATJANA; LEWEJOHANN, DAGMAR; GONZALEZ, DANIEL H.; BRAUN, HANS-PETER
Revista:
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 1817 p. 990 - 1001
ISSN:
0005-2728
Resumen:
We studied the role of cytochrome c (CYTc), which mediates electron
transfer between Complexes III and IV, in cellular events related with
mitochondrial respiration, plant development and redox homeostasis. We analyzed
single and double homozygous mutants in both CYTc-encoding genes from Arabidopsis: CYTC-1 and CYTC-2. While
individual mutants were similar to wild-type, knock-out of both genes produced
an arrest of embryo development, showing that CYTc function is essential at
early stages of plant development. Mutants in which CYTc levels were extremely
reduced respective to wild-type had smaller rosettes with a pronounced decrease
in parenchymatic cell size and an overall delay in development. Mitochondria
from these mutants had lower respiration rates and a relative
increase in alternative
respiration. Furthermore, the decrease in CYTc severely affected the activity
and the amount of Complex IV, without affecting Complexes I and III. Reactive
oxygen species levels were reduced in these mutants, which showed induction of
genes encoding antioxidant enzymes. Ascorbic acid levels were not affected,
suggesting that a small amount of CYTc is enough to support its normal synthesis.
We postulate that, in addition to its role as an electron carrier between
Complexes III and IV, CYTc influences Complex IV levels in plants, probably
reflecting a role of this protein in Complex IV stability. This double function
of CYTc most likely explains why it is essential for plant survival.