PKA-mediated Autophagy in Aspergillus fumigates

Jianye Shao,Lin Sun,Wei Zhao,Bin Wang

doi:10.18483/ijsci.1488

Abstract

Autophagy is a ubiquitous, non-selective degradation process in eukaryotic cells that is conserved from yeast to man. Autophagy research has increased significantly in the last ten years, as autophagy has been connected with cancer, neurodegenerative disease and various human developmental processes. Autophagy also appears to play an important role in filamentous fungi, impacting growth, morphology and development. In this review, an autophagy model developed for the Aspergillus fumigatus is used as an intellectual framework to discuss autophagy in filamentous fungi. Studies imply that, similar to yeast, fungal autophagy is characterized by the presence of autophagosomes and controlled by the target of rapamycin (Tor) kinase. Autophagy is highly regulated and is under the control of a number of signaling pathways, including the Tor pathway, which coordinates cell growth with nutrient availability. The data shows that autophagy in A.fumigatus is also controlled by the cAMP-dependent protein kinase (PKA) pathway. Elevated levels of PKA activity inhibited autophagy and inactivation of the PKA pathway is sufficient to induce a robust autophagy response. In addition, fungal autophagy is apparently involved in protection against cell death and has significant effects on cellular growth and development. However, the only two putative autophagy proteins characterized in filamentous fungi are Atg1 and Atg8. Here we will discuss various strategies used to study and monitor fungal autophagy as well as the possible relationship between autophagy, physiology, and morphological development.

Highlights

Filamentous fungi play important roles in health care, agriculture, food production, and bioprocessing
The term autophagy can describe a number of cellular phenomena including: macroautophagy
Induction and inhibition of autophagy Autophagy is a broad term covering the processes by which organisms recycle their intracellular components through the vacuole/lysosome, which are essential for cellular survival under conditions that the nutrient supply becomes limiting(Iannitti et al, 2016)

Summary

Introduction

Filamentous fungi play important roles in health care, agriculture, food production, and bioprocessing. Fungi possess a nutrient recycling pathway called autophagy that may prolong cellular survival(Klionsky et al, 2016). Autophagy appears to be involved in nutrient recycling during starvation, and it has been suggested it may be involved in normal developmental processes. Induction and inhibition of autophagy Autophagy is a broad term covering the processes by which organisms recycle their intracellular components through the vacuole/lysosome, which are essential for cellular survival under conditions that the nutrient supply becomes limiting(Iannitti et al, 2016). With the vacuolar membrane and a single membrane structure, commonly referred to as an autophagic body, enters the lumen of the vacuole There, this structure is lysed and its contents recycled by vacuolar hydrolases to replenish the nutrient depletion or to stimulate cellular differentiation(Chamilos et al, 2016). Autophagy has been shown to precede autolysis, and may possibly play a role in the early onset of http://www.ijSciences.com autolysis(Fuller, Zhao, Askew, & Rhodes, 2009)

Autophagy in cellular differentiation

The Pka and Tor pathways independently target the Atg13 protein