A Transient Receptor Potential-like Calcium Ion Channel in the Filamentous Fungus Aspergillus nidulans.

Hongchen Wang,Ling Lu,Shizhu Zhang,Qiuyi Chen

doi:10.3390/jof7110920

Hongchen Wang, Ling Lu + Show 2 more

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https://doi.org/10.3390/jof7110920

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Abstract

Transient Receptor Potential (TRP) proteins constitute a superfamily that encodes transmembrane ion channels with highly diverse permeation and gating properties. Filamentous fungi possess putative TRP channel-encoded genes, but their functions remain elusive. Here, we report that a putative TRP-like calcium channel, trpR, in the filamentous fungus Aspergillus nidulans, performs important roles in conidiation and in adapting to cell wall disruption reagents in a high temperature-induced defect-dependent manner, especially under a calcium-limited culture condition. The genetic and functional relationship between TrpR and the previously identified high-affinity calcium channels CchA/MidA indicates that TrpR has an opposite response to CchA/MidA when reacting to cell wall disruption reagents and in regulating calcium transients. However, a considerable addition of calcium can rescue all the defects that occur in TrpR and CchA/MidA, meaning that calcium is able to bypass the necessary requirement. Nevertheless, the colocalization at the membrane of the Golgi for TrpR and the P-type Golgi Ca2+ ATPase PmrA suggests two channels that may work as ion transporters, transferring Ca2+ from the cytosol into the Golgi apparatus and maintaining cellular calcium homeostasis. Therefore, combined with data for the trpR deletion mutant revealing abnormal cell wall structures, TrpR works as a Golgi membrane calcium ion channel that involves cell wall integration.

Highlights

Transient receptor potential (TRP) proteins were first described in Drosophila [1], and the presence of their superfamilies, that possess highly diverse permeation and gating properties, has been reported in most eukaryotes [2,3,4]
We focused on the functions of AN9146 which we referred to as a trpR
TRP proteins constitute a superfamily that encodes transmembrane ion channels with very diverse permeation and gating properties [2,3,4]

Summary

Introduction

Transient receptor potential (TRP) proteins were first described in Drosophila [1], and the presence of their superfamilies, that possess highly diverse permeation and gating properties, has been reported in most eukaryotes [2,3,4]. Around 30 proteins have been reported to belong to the TRP superfamily and possess some similar structural characteristics. These proteins have been subdivided into eight major branches and are divided into three broad groups: group one includes TRPC, TRPA, TRPM, TRPN, TRPV, group two includes TRPP and TRPML, and group three is the TRPY subfamily which currently only has one member, TRPY1 (or Yvc). TRP proteins seem to be absent in archaea, bacteria or higher plants [2,6,7]. The mammalian TRP protein forms a tetramer, where each polypeptide

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