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Updated: May 22, 2026
Microscopy of Fission Yeast Sexual Lifecycle
Published on: March 9, 2016
Remarkably simple sequence requirement of the M-factor pheromone of Schizosaccharomyces pombe
Taisuke Seike1, Yoshikazu Yamagishi, Hideo Iio
1Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan.
Abstract:
The mating reaction is triggered by specific pheromones in a wide variety of organisms. Small peptides are used as mating pheromones in yeasts and fungi. In the fission yeast Schizosaccharomyces pombe, M-factor is a C terminally farnesylated nonapeptide secreted from M-cells, and its counterpart, P-factor, is a simple peptide composed of 23 amino acids. The primary structure requirements for the biological activity of pheromone peptides remain to be elucidated. Here, we conducted comprehensive substitution of each of the amino acids in M-factor peptide and inspected the mating ability of these missense mutants. Thirty-five sterile mutants were found among an array of 152 mutants with single amino acid substitutions. Mapping of the mutation sites clearly indicated that the sterile mutants were associated exclusively with four amino acid residues (VPYM) in the carboxyl-terminal half. In contrast, the substitution of four amino-terminal residues (YTPK) with any amino acid had no or only a slightly deleterious effect on mating. Furthermore, deletion of the three N-terminal residues caused no sterility, although truncation of a fourth residue had a marked effect. We conclude that a farnesylated hexapeptide (KVPYMC(Far)-OCH(3)) is the minimal M-factor that retains pheromone activity. At least 15 nonfunctional peptides were found to be secreted, suggesting that these mutant M-factor peptides are no longer recognized by the cognate receptor.
Insights
Researchers identified the minimal active form of yeast M-factor pheromone. A specific hexapeptide sequence is crucial for mating ability, revealing key structural requirements for pheromone function.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Pheromones are crucial signaling molecules that trigger mating reactions in many organisms.
- In yeasts like Schizosaccharomyces pombe, peptide pheromones (M-factor and P-factor) regulate sexual reproduction.
- Understanding the structural basis of pheromone activity is essential for deciphering yeast mating mechanisms.
Purpose of the Study:
- To determine the primary structure requirements for the biological activity of the M-factor pheromone in Schizosaccharomyces pombe.
- To identify the minimal peptide sequence essential for M-factor pheromone function.
- To investigate the role of specific amino acid residues in M-factor's interaction with its receptor.
Main Methods:
- Comprehensive single amino acid substitutions were performed on the M-factor peptide.
- The mating ability of 152 resulting missense mutants was assessed.
- Mutation sites were mapped to identify critical residues for pheromone activity.
Main Results:
- Thirty-five sterile mutants were identified among the 152 single amino acid substitution mutants.
- Sterility was exclusively linked to substitutions in four carboxyl-terminal residues (VPYM).
- Substitutions in the amino-terminal residues (YTPK) had minimal impact on mating ability.
- Deletion analysis revealed that a farnesylated hexapeptide (KVPYMC(Far)-OCH(3)) is the minimal active M-factor.
Conclusions:
- The carboxyl-terminal hexapeptide sequence (KVPYMC(Far)-OCH(3)) represents the minimal M-factor required for pheromone activity.
- Specific amino acid residues in the carboxyl-terminal half are critical for M-factor recognition and biological function.
- Mutant M-factor peptides may be nonfunctional due to a loss of recognition by the cognate receptor.
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