Fit proteins (facilitor of iron transport) found on Saccharomyces cerevisiae cell wall are mannoproteins implicated in the siderophore-iron bound transport. This domain family can be found in FIT1 and FIT2 proteins in Saccharomycetaceae. The FIT1-3 cell wall mannoproteins are attached to the beta-glucan layer through a GPI (glycosylphosphatidylinoisitol) anchor. They are very rich in serine and threonine residues (40-50 % serine and threonine) and bear several short repeat of 6-7 amino acids sequence. The exact domain function is unknown.

1: Cell Surface Interference with Plasma Membrane and Transport Processes in Yeasts. Francois JM; Adv Exp Med Biol. 2016;892:11-31. PMID:26721269