Disease relevance of YOS9

• YOS9, the putative yeast homolog of a gene amplified in osteosarcomas, is involved in the endoplasmic reticulum (ER)-Golgi transport of GPI-anchored proteins [1].

High impact information on YOS9

• When Hrd1p is uncoupled from the Yos9p surveillance complex, degradation can occur independently of the requirement for glycosylation [2].
• This core complex associates through Hrd3p with Yos9p, a substrate recognition protein in the ER lumen [3].
• For luminal ERAD substrates, this recognition depends on their folding and glycosylation status as well as on the conserved ER lectin Yos9p [2].
• We report that a key pathway of ER quality control consists of a two-lectin receptor system consisting of Yos9p and Htm1/Mnl1p that recognizes N-linked glycan signals embedded in substrates [4].
• Yos9 protein is important for glycoprotein degradation and may act via its MRH domain as a degradation lectin-like protein in the glycoprotein degradation pathway [5].

Associations of YOS9 with chemical compounds

• The yeast protein (Yos9) is a membrane-associated glycoprotein that localizes to the endoplasmic reticulum (ER) [1].
• Immunoprecipitation showed that Yos9 specifically associated with misfolded carboxypeptidase Y (CPY*), an ERAD substrate, but only when it carried Man8GlcNAc2 or Man5GlcNAc2 N-glycans [5].

Other interactions of YOS9

• Correspondingly, Gas1 processing is slowed in cells bearing a deletion in YOS9 [1].
• YOS9 interacts genetically with genes involved in ER-Golgi transport, particularly SEC34, whose temperature-sensitive mutant is rescued by YOS9 overexpression [1].
• As Yos9 is not a component of the Emp24 complex, it may act as a novel escort factor for GPI-anchored proteins in ER-Golgi transport in yeast and possibly in mammals [1].

References