Related Experiment Video

Updated: Jun 3, 2026

Small-Scale Plasma Membrane Preparation for the Analysis of Candida albicans Cdr1-mGFPHis
09:44

Small-Scale Plasma Membrane Preparation for the Analysis of Candida albicans Cdr1-mGFPHis

Published on: June 13, 2021

Damage to the glycoshield activates PMT-directed O-mannosylation via the Msb2-Cek1 pathway in Candida albicans

Pilar D Cantero1, Joachim F Ernst

  • 1Institut für Mikrobiologie, Molekulare Mykologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1/26.12, 40225 Düsseldorf, Germany.

Molecular Microbiology
|March 8, 2011
PubMed

Insights

Protein-O-mannosyltransferases (Pmt) regulate Candida albicans growth and antifungal resistance. Distinct signaling pathways control PMT1 and PMT2/PMT4 gene expression in response to cell wall damage.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Mycology

Background:

  • Protein-O-mannosyltransferases (Pmt) are crucial for secretory protein glycosylation in fungi.
  • Candida albicans possesses five Pmt isoforms with distinct roles in fungal physiology and virulence.
  • Glycostructure integrity is essential for fungal cell wall function and antifungal drug efficacy.

Purpose of the Study:

  • To investigate the differential regulation of major Protein-O-mannosyltransferase (Pmt) genes in Candida albicans.
  • To elucidate the signaling pathways controlling Pmt gene expression in response to impaired glycostructures.
  • To identify novel transcription factors involved in Pmt gene regulation.

Main Methods:

  • Analysis of PMT gene transcript levels in various Candida albicans mutants and under tunicamycin treatment.
  • Utilizing reporter gene fusions to identify regulatory promoter sequences.
  • Investigating the role of Cek1 MAP kinase, Msb2, and Ace2 in Pmt gene expression.
  • Assessing the sensitivity of mutant strains to cell wall and glycosylation inhibitors.

Main Results:

  • PMT1 transcript levels increased in cell wall mutants and upon N-glycosylation inhibition, while PMT2 and PMT4 were upregulated by Pmt1 inhibition.
  • Specific promoter elements regulate PMT1 repression, which is relieved by tunicamycin.
  • The Msb2-Cek1 pathway is essential for PMT1 de-repression and PMT2/PMT4 induction.
  • Ace2 acts as a novel transcription factor upregulating PMT basal expression and induction.
  • Mutants lacking Msb2, Cek1, and Ace2 exhibited hypersensitivity to cell wall and glycosylation inhibitors.

Conclusions:

  • Distinct regulatory mechanisms govern PMT1 and PMT2/PMT4 gene expression in Candida albicans.
  • A Msb2-Cek1-Ace2 signaling cascade targets PMT genes, responding to glycostructure damage.
  • This pathway is critical for maintaining cell wall integrity and antifungal resistance.

More Related Videos

Genetic Manipulation of the Plant Pathogen Ustilago maydis to Study Fungal Biology and Plant Microbe Interactions11:42

Genetic Manipulation of the Plant Pathogen Ustilago maydis to Study Fungal Biology and Plant Microbe Interactions

Published on: September 30, 2016

Live-cell Video Microscopy of Fungal Pathogen Phagocytosis08:52

Live-cell Video Microscopy of Fungal Pathogen Phagocytosis

Published on: January 9, 2013

Related Concept Videos

Export of Misfolded Proteins out of the ER01:32

Export of Misfolded Proteins out of the ER

After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...
Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
Oligosaccharide Assembly01:24

Oligosaccharide Assembly

Protein glycosylation starts in the ER lumen and continues in the Golgi apparatus. Glycosyltransferases catalyze the addition of sugar molecules or glycosylation of proteins. Usually, these enzymes add sugars to the hydroxyl groups of selected serine or threonine residues to form O-linked glycans or the amino groups of asparagine residues to form N-linked glycans. Different positions on the same polypeptide chain can contain differently linked glycans.
Multiple sugar molecules that may or may...
Yeast Signaling01:28

Yeast Signaling

Yeasts are single-celled organisms, but unlike bacteria, they are eukaryotes (cells with a nucleus). Cell signaling in yeast is similar to signaling in other eukaryotic cells. A ligand, such as a protein or a small molecule released from a yeast cell, attaches to a receptor on the cell surface. The binding stimulates second-messenger kinases to activate or inactivate transcription factors that further regulate gene expression. Many of the yeast intracellular signaling cascades have similar...
Regulated Protein Degradation02:58

Regulated Protein Degradation

It is vital to regulate the activity of enzymatic as well as non-enzymatic proteins inside the cell. This can be achieved either through creating a balance between their rate of synthesis and degradation or regulating the intrinsic activity of the protein. Both these regulation mechanisms play an essential role in the normal functioning of cells.
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
The Proteasome01:13

The Proteasome

Eukaryotic cells can degrade proteins through several pathways. One of the most important among these is the ubiquitin-proteasome pathway. It helps the cell eliminate the misfolded, damaged, or unwarranted cytoplasmic proteins in a highly specific manner.
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin...