ROS signal transduction and cell differentiation in filamentous fungi

Ref ID: 18442


Fernando Lara-Rojas, Olivia Sánchez, Jesús Aguirre

Author address:

Instituto de Fisiologí­a Celular, Universidad Nacional Autónoma de México

Full conference title:

11 th European Conference on Fungal Genetics


A phosphorelay system coupled to a MAP kinase module is involved in sensing and processing environmental
signals in Fungi. In Aspergillus nidulans, response regulator (RR) SskA transmits oxidative stress signals to the stress
MAPK (SAPK) SakA, which in turns physically interacts with ATF/CREB transcription factor AtfA in the nucleus. This
defines a general stress8208;signalling pathway, which plays differential roles in oxidative stress responses during
growth and development. AtfA is needed for the expression of several genes, the conidial accumulation of SakA
and the viability of conidia. Furthermore, SakA is active (phosphorylated) in asexual spores, remaining
phosphorylated in dormant conidia and becoming dephosphorylated during germination. SakA phosphorylation in
spores depends on certain (SskA) but not other (SrrA and NikA) components of the phosphorelay system.
Constitutive phosphorylation of SakA prevents both, germ tube formation and nuclear division. Similarly,
Neurospora crassa SakA orthologue OS8208;2 is phosphorylated in intact conidia and gets dephosphorylated during
germination. We propose that SAPK phosphorylation is a conserved mechanism to regulate transitions between
non8208;growing (spore) and growing (mycelia) states. The Aspergilli contain a second SAPK called MpkC. Although
mpkC mutants are not sensitive to oxidative or osmotic stress, they produce more spores that the wild type strain,
suggesting that SakA and MpkC regulate processes related to the production and germination of spores. In
addition, to the SakA pathway, RR SrrA and the AP8208;1 trancription factor NapA are differentially involved in ROS
signalling and cell differentiation.  Â 

Abstract Number: PS6.1

Conference Year: 2012

Link to conference website:

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