Table 1

Adhesins in C. albicans

Protein name(s)aStructural propertiesbSubstrate and/or functional propertiescReference(s)
Als familyd21
    Als11,260 aa; contains amyloid-forming sequencesEndothelial and epithelial cells; fibronectin-, laminin-, and fucose-containing glycans; abiotic surfaces such as glass and plastics; cell-cell interaction; biofilm induced; contributes to biofilm formation and pathogenesis32, 3436, 37, 38, 3941, 42
    Als2∼2,531 aa (Als2 in CGD is incomplete; length inferred from comparison to Als2 in strain 1161 (GenBank accession no. AAC64236)Endothelial cells; abiotic surfaces such as glass and plastics; contributes to biofilm formation and pathogenesis35, 36, 37
    Als31,155 aa; contains amyloid-forming sequencesEndothelial and epithelial cells; fibronectin, laminin, saliva-coated particles, and type IV collagen; abiotic surfaces such as glass and plastics; Streptococcus gordonii and Staphylococcus aureus; cell-cell interaction; transferrin receptor in iron acquisition; invasin; induction of C. albicans endocytosis; host cell damage; contributes to biofilm formation and pathogenesis; hypha specific26, 35, 43, 37, 41, 4447, 48, 49
    Als42,100 aaEndothelial cells; abiotic surfaces such as glass and plastics; functional overlap with Als236, 37
    Als51,347 aa; contains amyloid-forming sequencesExtracellular matrix proteins; abiotic surfaces such as such as glass and plastics; deletion mutant more adherent to endothelial and epithelial cells; aggregation; contributes to biofilm formation and pathogenesis50, 43, 37, 51, 5254
    Als61,366 aaGelatin; abiotic surfaces such as glass and plastics; deletion mutant more adherent to endothelial and epithelial cells43, 37, 54
    Als71,568 aa; copy numbers of TR units are highly variableAbiotic surfaces such as glass and plastics; deletion mutant more adherent to endothelial and epithelial cells43, 37, 54, 55
    Als91,890 aa; allelic diversity; N-terminal ligand binding (Als9-2)Endothelial cells (N-terminal Als9-2); laminin; abiotic surfaces such as glass and plastics32, 37, 54
Hwp1 familye41, 56
    Hwp1634 aa; glutamine-rich N-terminal domain serves as host transglutaminase substrate; putative site for proteolytic processing; 2 Hwp1 repeatsSaliva- or fibronectin-coated surfaces; buccal epithelial cells displaying keratin 13 and SRP3; polystyrene, but less binding to silicone; low attachment to Streptococcus gordonii; role in biofilm formation; hypha specific; Tup1 repressed26, 40, 5760
    Hwp2/Pga8908 aa; short N-terminal high-complexity region; putative site for proteolytic processing; 2 Hwp1 repeatsEpithelial cells; polystyrene; role in biofilm formation on silicone; expressed in hyphae61, 57, 62, 63
    Rbt1721/714 aa; N-terminal high-complexity region; putative sites for proteolytic processing; propeptide found in growth medium; 2 Hwp1 repeatsSerum; hypha induced; Tup1 repressed; required for full virulence57, 64, 63, 65
    Eap1/Pga47653/1,121 aa; alleles differ in number of 6-aa repeats; short N-terminal high-complexity region; putative site for proteolytic processing; 2 Hwp1 repeatsEpithelial cells; Streptococcus gordonii; polystyrene; role in biofilm formation, filamentation, and mating26, 66, 6770
    Ywp1/Pga24533 aa; N-terminal high-complexity region; 2 sites for proteolytic processing; propeptide found in growth medium; Sap9 cleaved; 2 Hwp1 repeatsMutant shows increased adhesion and biofilm formation; expressed in yeast cells71, 56
Iff/Hyr familyf
    Hyr1919 aaMediates resistance to neutrophil killing; anti-Hyr1 AB is immunoprotective; hypha specific; Bcr1 dependent40, 72, 73, 74
    Rbr3/Iff11,562 aa; 10 Iff/Hyr repeats; 2 putative sites for proteolytic processingUpregulated at low pH; expression is repressed by Rim101 and activated by Nrg175, 76
    Hyr3/Iff21,249 aa; 4 Iff/Hyr repeats; putative proteolytic-processing site75
    Iff3941 aa; 2 Iff/Hyr repeats; putative site for proteolytic processing75
    Iff41.526 aaEpithelial cells; plastics; implicated in virulence7779
    Iff51,308 aa; 5 Iff/Hyr repeats75
    Iff61,086 aa; putative site for proteolytic processing
    Hyr4/Iff71,225 aa; 3 Iff/Hyr repeats75
    Iff8714 aa
    Iff9940 aa; 2 Iff/Hyr repeats75
    Flo9/Iff101,244 aa
    Iff11511 aa; no GPI anchor peptide; secreted proteinRequired for normal cell wall structure and virulence80
  • a Protein names are from the Candida Genome Database (CGD) (http://www.candidagenome.org/).

  • b All listed proteins contain signal peptides for ER entry; all except Iff11 contain C-terminal signals for GPI anchoring.

  • c Only the most relevant phenotypes are listed.

  • d Als family proteins share similar domain structures with N-terminal effector domains that are 55 to 90% identical across the whole family, central domains with tandem repeats (TR), and variable Ser/Thr-rich C-terminal domains.

  • e Hwp1 family proteins have in common the presence of one or more Hwp1 repeats.

  • f Iff/Hyr family proteins share a protein structure with a conserved putative N-terminal effector domain followed by a low-complexity C-terminal domain. The latter may contain a variable number of Iff/Hyr repeats.