Students learn that membrane proteins are inserted into the endoplasmic-reticulum (ER) membrane co-translationally, but this mechanism does not hold for so-called tail-anchored (TA) proteins which carry a single C-terminal membrane spanning domain and insert into the ER membrane post-translationally. The mechanism of TA protein insertion was recently described in yeast as the GET (Guided Entry of Tail-anchored) system, which includes a protein complex that binds to and shields the transmembrane domain, a protein (GET3) that shuttles the protein to the ER, and ER-bound receptors that complete the insertion of the TA protein. Srivistava et al. (Plant Physiol 10.1104/pp.16.00928) recently demonstrated that in Arabidopsis the GET system is involved in the ER-membrane insertion of the TA protein SYP72. Xing et al. (Proc. Natl. Acad. Sci. USA 10.1073/pnas.1619525114) found that plants have two GET3 clades, a duplication that is also present in Lokiarchaeota (sister/precursor to eukaryotes), suggesting that rather than a plant-specific duplication, animals and fungi have lost one clade. Xing et al. also functionally characterize the genes encoding GET3 and other GET pathway components. Although get3 knock outs show only a modest root hair phenotype (suggesting an alternate route for TA protein insertion), plants are severely affected when GET3 is overexpressed in a get1 receptor mutant background, possibly due to accumulation of cytosolic aggregates of TA proteins.
You might also like
Evolution of carnivorous traps from planar leaves through simple shifts in gene expression (Science)
Jasmonate-related MYC transcription factors are functionally conserved in Marchantia polymorpha ($) (Plant Cell)
Review - Getting to the Roots: A Developmental Genetic View of Root Anatomy and Function From Arabidopsis to Lycophytes (Frontiers in Plant Sci)