High impact information on OST6

• In the case of Ost5p and Ost6p, both their N and C termini are present in the cytosol [1].
• These findings also suggested that Ost2p, Stt3p, Ost5p, and Ost6p do not have a cleavable N-terminal signal sequence [1].
• Interestingly, Ost3p and Ost6p subunits exhibited a surprisingly identical pattern of cross-linking to other subunits, which is consistent with their proposed redundant function [2].
• The OST6-complex was found to be important for cell wall integrity and temperature stress [3].
• By blue native polyacrylamide electrophoresis we show that yeast OST consists of two isoforms with distinct functions differing only in the presence of the two related Ost3 and Ost6p proteins [3].

Biological context of OST6

• Disruption of OST6 or OST3 causes only a minor defect in N-glycosylation, but an Deltaost3Deltaost6 double mutant displays a synthetic phenotype, leading to a severe underglycosylation of soluble and membrane-bound glycoproteins in vivo and to a reduced OST activity in vitro [4].

Other interactions of OST6

• In this study we report the identification and functional characterization of a new OST gene, designated OST6, that has homology to OST3 and in particular a strikingly similar membrane topology [4].
• We demonstrate that the small 3.4-kDa subunit Ost4p is required for the incorporation of either Ost3p or Ost6p into the complex, resulting in two, functionally distinct OTase complexes in vivo [5].

References