Characterisation of CwpA, a putative glycosylphosphatidylinositol-anchored cell wall mannoprotein in the filamentous fungus Aspergillus niger

• Published in: Fungal genetics and biology 2005-10, Vol.42 (10), p.873-885
• Main Authors: Damveld, Robbert A., Arentshorst, Mark, VanKuyk, Patricia A., Klis, Frans M., van den Hondel, Cees A.M.J.J., Ram, Arthur F.J.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; amino acid sequences; Aspergillus niger; Aspergillus niger - chemistry; Aspergillus niger - genetics; Base Sequence; Calcofluor White; Cell Wall - chemistry; Cell wall integrity; cell walls; DNA, Fungal - chemistry; DNA, Fungal - genetics; Fungal Proteins - chemistry; Fungal Proteins - genetics; Fungal Proteins - isolation & purification; Gene Deletion; Glucan; glycoproteins; Glycosylphosphatidylinositols; GPI-anchoring; HF-extractions; Hydrofluoric Acid; Hypersensitive; mannoproteins; mannose; Membrane Glycoproteins - chemistry; Membrane Glycoproteins - genetics; Membrane Glycoproteins - isolation & purification; Molecular Sequence Data; phosphatidylinositols; Phylogeny; Protein Sorting Signals - genetics; Sequence Analysis, DNA; ω-site
• ISSN: 1087-1845; 1096-0937
• DOI: 10.1016/j.fgb.2005.06.006

Glycosylphosphatidylinositol (GPI)-anchored proteins in fungi are found at the cell surface, either as plasma membrane proteins (GPI-PMPs) or attached by a remnant of the GPI-anchor to the cell wall (GPI-CWPs). GPI-CWPs can be extracted from the cell wall by treatment with hydrofluoric acid (HF), which cleaves the phosphodiester bond that is present in the remnant of the GPI-anchor. The filamentous fungus Aspergillus niger contains at least seven HF-extractable cell wall mannoproteins. One gene encoding an HF-extractable cell wall mannoprotein, cwpA, was cloned and further characterised. The protein sequence of CwpA indicated the presence of two hydrophobic signal sequences both at the N-terminus and C-terminus of the protein, for entering the ER and the addition of a GPI-anchor, respectively. A CwpA-specific antiserum was raised and in combination with fractionation experiments, we show that this protein was abundantly present as an HF-extractable protein in the cell wall of A. niger.