Putative PmrA and PmcA are important for normal growth, morphogenesis and cell wall integrity, but not for viability in Aspergillus nidulans

Abstract

P-type Ca2+-transporting ATPases are Ca2+ pumps, extruding cytosolic Ca2+ to the extracellular environment or the intracellular Ca2+ store lumens. In budding yeast, Pmr1 (plasma membrane ATPase related), and Pmc1 (plasma membrane calcium-ATPase) cannot be deleted simultaneously for it to survive in standard medium. Here, we deleted two putative Ca2+ pumps, designated AnPmrA and AnPmcA, from Aspergillus nidulans, and obtained the mutants ΔanpmrA and ΔanpmcA, respectively. Then, using ΔanpmrA as the starting strain, the promoter of its anpmcA was replaced with the alcA promoter to secure the mutant ΔanpmrAalcApmcA or its anpmcA was deleted completely to produce the mutant ΔanpmrAΔpmcA. Different from the case in Saccharomyces cerevisiae, double deletion of anpmrA and anpmcA was not lethal in A. nidulans. In addition, deletion of anpmrA and/or anpmcA had produced growth defects, although overexpression of AnPmc1 in ΔanpmrAalcApmcA could not restore the growth defects that resulted from the loss of AnPmrA. Moreover, we found AnPmrA was indispensable for maintenance of normal morphogenesis, especially in low-Ca2+/Mn2+ environments. Thus, our findings suggest AnPmrA and AnPmcA might play important roles in growth, morphogenesis and cell wall integrity in A. nidulans in a different way from that in yeasts.

The Lectin Chaperone Calnexin Is Involved in the Endoplasmic Reticulum Stress Response by Regulating Ca 2+ Homeostasis in Aspergillus nidulans

“…To investigate the link between clxA and pmrA, we crossed the ΔclxA and ΔpmrA mutants. Consistent with our previous report (38), the ΔpmrA mutant showed a slight reduction in hyphal radial growth and conidiation compared to the wild-type strain. Expectedly, the ΔclxA ΔpmrA double deletion mutant showed a further decrease in the hyphal radial growth and conidiation on MM compared to that seen in the single mutants ( Fig.…”

Palmitoylation of the Cysteine Residue in the DHHC Motif of a Palmitoyl Transferase Mediates Ca2+ Homeostasis in Aspergillus

“…In A . nidulans , Δ pmrA had no discernible effect on fungal physiology, but the cells were hypersensitive to low extracellular calcium [ 38 ]. To investigate the link between AkrA and PmrA, we crossed the Δ akrA and Δ pmrA mutants.…”

Calcium Transport Proteins in Fungi: The Phylogenetic Diversity of Their Relevance for Growth, Virulence, and Stress Resistance

“…These growth defects can be rescued in B. bassiana and N. crassa by addition of Mn 2+ or Ca 2+ (Bowman et al, 2012;Wang et al, 2013). Interestingly, growth defects in A. fumigatus and Aspergillus nidulans can be recovered by osmotic stabilization, but not by Ca 2+ or Mn 2+ (Pinchai et al, 2010;Jiang et al, 2014a). As in yeasts, Pmr1 is needed in filamentous fungi to resist cell wall stress.…”