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PalC, One of Two Bro1 Domain Proteins in the Fungal pH Signalling Pathway, Localizes to Cortical Structures and Binds Vps32
Author(s) -
Galindo Antonio,
HervásAguilar América,
RodríguezGalán Olga,
Vincent Olivier,
Arst Herbert N.,
Tilburn Joan,
Peñalva Miguel A.
Publication year - 2007
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2007.00620.x
Subject(s) - escrt , endosome , biology , microbiology and biotechnology , saccharomyces cerevisiae , transmembrane protein , membrane protein , transmembrane domain , receptor , endocytic cycle , signal transducing adaptor protein , plasma protein binding , biochemistry , signal transduction , yeast , membrane , endocytosis
PalC, distantly related to Saccharomyces cerevisiae peripheral endosomal sorting complexes required for transport III (ESCRT‐III) component Bro1p and one of six Aspergillus nidulans pH signalling proteins, contains a Bro1 domain. Green fluorescent protein (GFP)‐tagged PalC is recruited to plasma membrane‐associated punctate structures upon alkalinization, when pH signalling is active. PalC recruitment to these structures is dependent on the seven transmembrane domain (7‐TMD) receptor and likely pH sensor PalH. PalC is a two‐hybrid interactor of the ESCRT‐III Vps20/Vps32 subcomplex and binds Vps32 directly. This binding is largely impaired by Pro439Phe, Arg442Ala and Arg442His substitutions in a conserved region mediating interaction of Bro1p with Vps32p, but these substitutions do not prevent cortical punctate localization, indicating Vps32 independence. In contrast, Arg442Δ impairs Vps32 binding and prevents PalC‐GFP recruitment to cortical structures. pH signalling involves a plasma membrane complex including the 7‐TMD receptor PalH and the arrestin‐like PalF and an endosomal membrane complex involving the PalB protease, the transcription factor PacC and the Vps32 binding, Bro1‐domain‐containing protein PalA. PalC, which localizes to cortical structures and can additionally bind a component of ESCRT‐III, has the features required to bridge these two entities. A likely S. cerevisiae orthologue of PalC has been identified, providing the basis for a unifying hypothesis of gene regulation by ambient pH in ascomycetes.