The contribution of the O-glycosylated protein Pir2p/Hsp150 to the construction of the yeast cell wall in wild-type cells and beta 1,6-glucan-deficient mutants

Mol Microbiol. 1999 Mar;31(6):1835-44. doi: 10.1046/j.1365-2958.1999.01320.x.


The cell wall of yeast contains a major structural unit, consisting of a cell wall protein (CWP) attached via a glycosylphosphatidylinositol (GPI)-derived structure to beta 1,6-glucan, which is linked in turn to beta 1, 3-glucan. When isolated cells walls were digested with beta 1,6-glucanase, 16% of all CWPs remained insoluble, suggesting an alternative linkage between CWPs and structural cell wall components that does not involve beta 1,6-glucan. The beta 1,6-glucanase-resistant protein fraction contained the recently identified GPI-lacking, O-glycosylated Pir-CWPs, including Pir2p/Hsp150. Evidence is presented that Pir2p/Hsp150 is attached to beta 1,3-glucan through an alkali-sensitive linkage, without beta 1,6-glucan as an interconnecting moiety. In beta 1,6-glucan-deficient mutants, the beta 1,6-glucanase-resistant protein fraction increased from 16% to over 80%. This was accompanied by increased incorporation of Pir2p/Hsp150. It is argued that this is part of a more general compensatory mechanism in response to cell wall weakening caused by low levels of beta 1,6-glucan.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkalies / pharmacology
  • Blotting, Northern
  • Blotting, Western
  • Cell Wall / physiology
  • Chitin / metabolism
  • Glucans / genetics
  • Glucans / metabolism*
  • Glucosyltransferases*
  • Glycoproteins*
  • Glycosylation
  • Heat-Shock Proteins / metabolism*
  • Membrane Proteins / metabolism
  • Models, Genetic
  • Mutagenesis
  • RNA, Messenger / metabolism
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins*
  • beta-Glucans*


  • Alkalies
  • Glucans
  • Glycoproteins
  • HSP150 protein, S cerevisiae
  • Heat-Shock Proteins
  • Membrane Proteins
  • RNA, Messenger
  • Saccharomyces cerevisiae Proteins
  • beta-Glucans
  • Chitin
  • beta-1,6-glucan
  • Glucosyltransferases
  • GSC2 protein, S cerevisiae