Comparison of cell wall localization among Pir family proteins and functional dissection of the region required for cell wall binding and bud scar recruitment of Pir1p.
We examined the localization of the Pir protein family (Pir1 to Pir4), which is covalently linked to the cell wall in an unknown manner. In contrast to the other Pir proteins, a fusion of Pir1p and monomeric red fluorescent protein distributed in clusters in pir1Delta cells throughout the period of cultivation, indicating that Pir1p is localized in bud scars. Further microscopic analysis revealed that Pir1p is expressed inside the chitin rings of the bud scars. Stepwise deletion of the eight units of the repetitive sequence of Pir1p revealed that one unit is enough for the protein to bind bud scars and that the extent of binding of Pir1p to the cell wall depends on the number of these repetitive units. The localization of a chimeric Pir1p in which the repetitive sequence of Pir1p was replaced with that of Pir4p revealed the functional role of the different protein regions, specifically, that the repetitive sequence is required for binding to the cell wall and that the C-terminal sequence is needed for recruitment to bud scars. This is the first report that bud scars contain proteins like Pir1p as internal components.
Sumita
Toru
T
Research Center for Glycoscience, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 6, Tsukuba, Ibaraki 305-8566, Japan.
Yoko-o
Takehiko
T
Shimma
Yoh-ichi
Y
Jigami
Yoshifumi
Y
D000595:Amino Acid Sequence; D002455:Cell Division / Q000502:physiology; D016764:Cell Polarity; D002473:Cell Wall / Q000378:metabolism*; D002686:Chitin / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D006023:Glycoproteins; D008969:Molecular Sequence Data; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment
D005656:Fungal Proteins; D006023:Glycoproteins; C423367:PIR1 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D002686:Chitin