This presumed domain is found at the N-terminus of the S. cerevisiae Flo11 protein. Flo11 is required for diploid pseudohyphal formation and haploid invasive growth. It belongs to a family of proteins involved in invasive growth, cell-cell adhesion, and mating, many of which can substitute for each other under abnormal conditions (PUBMED:11027318).
Fungal cells need to be able to adhere to their surroundings, be it either abiotic surfaces or living tissues, in order to remain firmly attached to their source of nutrients. Adhesive properties in fungi are conveyed by a group of cell-surface proteins called adhesins (sometimes also referred to as agglutinins or flocculins). Adhesins are generally rich in serine and threonine residues that allow extensive O-linked glycosylation. Some fungal adhesins also carry discernable ligand-binding domains that determine their substrate specificity and allows some degree of sequence classification of the different groups of adhesins.
Flocculin 11 is the major adhesin for controlling filamentous growth, mat, and biofilm formation of bakers's yeast. Although its amino acid sequence shows less similarity with the other flocculins, Flo11 belongs to the flocculin family. However, the N-terminal domain contains the 'Flo11 domain', but not the mannose-binding PA14 domain, which is present in most other flocculins (Flo1, Flo5, Flo9 and Flo10). Flo11 domains are only found within the ascomycetal orders of Saccharomycetales, which include the budding yeasts as well as the Schizosaccharomycetales, i.e. the fission yeast Schizosaccharomyces pombe. In the majority of its family members, the Flo11 domain is located at the N- terminal ends of glycosylphosphatidylinositol (GPI)-anchored cell wall proteins, although some yeasts such as Clavispora lusitaniae or Spathaspora passalidarum have arrays of up to three Flo11 domains within their adhesins. The Flo11 domain is not a mannose-binding module but can make homotypic interactions [(PUBMED:17870620), (PUBMED:22129043), (PUBMED:25960408)].
The Flo11 domain consists of some 160 amino acids. It is O-glycosylated and is structurally composed mainly of beta-sheets, which is typical for the members of the flocculin family. The Flo11 domain structure corresponds to a globular, wedge-shaped domain with a complex folding motif that consists of three anti- parallel beta sheets. The sheets I and II form a beta sandwich as core domain, whereas the four-pleated sheet III forms a unique, neck-like subdomain along the lower end of the beta sandwich. The core domain, namely the beta-sandwich formed by the anti-parallel beta sheets I and II, was assigned to the class of fibronectin type III-like domains (FN3) [(PUBMED:25960408)].
There are 128 Flo11 domains in 102 proteins in SMART's nrdb database.
Taxonomic distribution of proteins containing Flo11 domain.
This tree includes only several representative species. The complete taxonomic breakdown of all proteins with Flo11 domain is also avaliable.
Click on the protein counts, or double click on taxonomic names to display all proteins containing Flo11 domain in the selected taxonomic class.
Molecular phylogenetics of ascomycotal adhesins--a novel family of putativecell-surface adhesive proteins in fission yeasts.
In this work, we identify a family of putative adhesins in the fission yeastsSchizosaccharomyces pombe and Schizosaccharomyces japonicus. The members of this family share a conserved tandem repeat related to those found in the Candidaalbicans Als family of adhesins. Unlike previously characterised adhesins thatpossess conserved ligand-binding domains at the N-terminus, this group ofproteins carry ligand-binding domains at their C-termini. We demonstrate that onesuch domain--the uncharacterised GLEYA domain, is related to the lectin-likeligand-binding domain found in the Saccharomyces cerevisiae Flo proteins. Unlike the Flo and Als proteins, the fission yeast adhesins do not contain detectableglycosyl phosphatidyl inositol (GPI) membrane anchor signals to mediate theirattachment to the cell wall, which may suggest a novel cell wall attachmentmechanism. Further sequence analysis identified several putative adhesins in the sub-phylum of Pezizomycotina, where only a few adhesins have been described todate.
A Saccharomyces gene family involved in invasive growth, cell-cell adhesion, and mating.
The cell wall of bakers' yeast contains a family of glycosyl-phosphatidylinositol(GPI)-linked glycoproteins of domain structure similar to the adhesins ofpathogenic fungi. In wild-type cells each of these proteins has a unique functionin different developmental processes (mating, invasive growth, cell-celladhesion, or filamentation). What unifies these developmental events is adhesion,either to an inert substrate or to a cell. Although they differ in theirspecificities, many of these proteins can substitute for each other whenoverexpressed. For example, Flo11p is required during vegetative growth forhaploid invasion and diploid filamentation, whereas Fig2p is required for mating.When overexpressed, Flo11p and Fig2p can function in mating, invasion,filamentation, and flocculation. The ability of Flo11p to supply Fig2p functionin mating depends on its intracellular localization to the mating projection,where Fig2p normally functions in the adhesion of mating cells. Our data showthat even distant family members retain the ability to carry out disparatefunctions if localized and expressed appropriately.
The cell surface flocculin Flo11 is required for pseudohyphae formation andinvasion by Saccharomyces cerevisiae.
Diploid yeast develop pseudohyphae in response to nitrogen starvation, whilehaploid yeast produce invasive filaments which penetrate the agar in rich medium.We have identified a gene, FLO11, that encodes a cell wall protein which iscritically required for both invasion and pseudohyphae formation in response tonitrogen starvation. FLO11 encodes a cell surface flocculin with a structuresimilar to the class of yeast serine/threonine-rich GPI-anchored cell wallproteins. Cells of the Saccharomyces cerevisiae strain Sigma1278b with deletions of FLO11 do not form pseudohyphae as diploids nor invade agar as haploids. Inrich media, FLO11 is regulated by mating type; it is expressed in haploid cellsbut not in diploids. Upon transfer to nitrogen starvation media, however, FLO11transcripts accumulate in diploid cells, but not in haploids. Overexpression ofFLO11 in diploid cells, which are otherwise not invasive, enables them to invade agar. Thus, the mating type repression of FLO11 in diploids grown in rich mediasuffices to explain the inability of these cells to invade. The promoter of FLO11contains a consensus binding sequence for Ste12p and Tec1p, proteins known tocooperatively activate transcription of Ty1 elements and the TEC1 gene duringdevelopment of pseudohyphae. Yeast with a deletion of STE12 does not expressFLO11 transcripts, indicating that STE12 is required for FLO11 expression. These ste12-deletion strains also do not invade agar. However, the ability to invadecan be restored by overexpressing FLO11. Activation of FLO11 may thus be theprimary means by which Ste12p and Tec1p cause invasive growth.
Muc1, a mucin-like protein that is regulated by Mss10, is critical forpseudohyphal differentiation in yeast.
Pseudohyphal differentiation in Saccharomyces cerevisiae was first described as aresponse of diploid cells to nitrogen limitation. Here we report that haploid anddiploid starch-degrading S. cerevisiae strains were able to switch from a yeastform to a filamentous pseudohyphal form in response to carbon limitation in thepresence of an ample supply of nitrogen. Two genes, MSS10 and MUC1, were clonedand shown to be involved in pseudohyphal differentiation and invasive growth. Thedeletion of MSS10 resulted in extremely reduced amounts of pseudohyphaldifferentiation and invasive growth, whereas the deletion of MUC1 abolishedpseudohyphal differentiation and invasive growth completely. Mss10 appears to be a transcriptional activator that responds to nutrient limitation and coregulates the expression of MUC1 and the STA1-3 glucoamylase genes, which are involved instarch degradation. MUC1 encodes a 1367-amino acid protein, containing severalserine/threonine-rich repeats. Muc1 is a putative integral membrane-boundprotein, similar to mammalian mucin-like membrane proteins that have beenimplicated to play a role in the ability of cancer cells to invade other tissues.
FLO11, a yeast gene related to the STA genes, encodes a novel cell surfaceflocculin.
We report the characterization of a gene encoding a novel flocculin related tothe STA genes of yeast, which encode secreted glucoamylase. The STA genescomprise sequences that are homologous to the sporulation-specific glucoamylaseSGA and to two other sequences, S2 and S1. We find that S2 and S1 are part of asingle gene which we have named FLO11. The sequence of FLO11 reveals a 4,104-bpopen reading frame on chromosome IX whose predicted product is similar in overallstructure to the class of yeast serine/threonine-rich GPI-anchored cell wallproteins. An amino-terminal domain containing a signal sequence and acarboxy-terminal domain with homology to GPI (glycosyl-phosphatidyl-inositol)anchor-containing proteins are separated by a central domain containing a highly repeated threonine- and serine-rich sequence. Yeast cells that express FLO11aggregate in the calcium-dependent process of flocculation. Flocculation isabolished when FLO11 is disrupted. The product of STA1 also is shown to haveflocculating activity. When a green fluorescent protein fusion of FLO11 wasexpressed from the FLO11 promoter on a single-copy plasmid, fluorescence wasobserved in vivo at the periphery of cells. We propose that FLO11 encodes aflocculin because of its demonstrated role in flocculation, its structuralsimilarity to other members of the FLO gene family, and the cell surface locationof its product. FLO11 gene sequences are present in all yeast strains tested,including all standard laboratory strains, unlike the STA genes which are presentonly in the variant strain Saccharomyces cerevisiae var. diastaticus. FLO11differs from all other yeast flocculins in that it is located near a centromererather than a telomere, and its expression is regulated by mating type.Repression of FLO11-dependent flocculation in diploids is conferred by themating-type repressor al/alpha2.