9.B.308. The Lettuce Infectious Yellows Virus P5 (LIYV-P5) Family
The LIYV P5 protein is 39 aas long and has 1 TMS. It is part of the conserved quintuple gene block in the family Closteroviridae. The LIYV P5 protein is an endoplasmic reticulum (ER)-localized integral transmembrane protein. The knockout LIYV mutant presented reduced symptom severity and virus accumulation in Nicotiana benthamiana or lettuce plants, indicating its importance in efficient virus infection. P5, as well as its ortholog P6, encoded by Citrus tristeza virus (CTV) and another ER-localized protein encoded by LIYV RNA1, were found to cause cell death when expressed in N. benthamiana plants from a TMV vector, and it induced ER stress as well as the unfolded protein response (UPR) (Qiao et al. 2018). Several putative orthologues in different viruses are mentioned by Qiao et al. 2018, and these are presented in this family, although most of them show minimal sequence similarity.
The P5 protein of 39 aas and 1 N-terminal TMS. It may be capable of forming an oligomeric channel in plant cell membranes, causing ER stress and inducing cell death (Qiao et al. 2018).
P5 of Lettuce infectious yellows virus
P6 protein of 51 aas and 1 N-terminal TMS.
P6 of the Citrus tristeza virus
P6 protein of 56 aas and 1 N-terminal TMS.
P6 protein of the fig mild mottle-associated virus
ER movement protein p6 (6 kDa protein) of 54 aas and 1 N-terminal TMS.
P6 of beet yellows virus
The P4 protein of 37 aas and 1 N-terminal TMS.
P4 protein of Cordyline virus 1
4.2 kDa transmembrane protein of 35 aas and 1 N-terminal TMS.
Protein of Cordyline virus 2
P5 protein of 44 aas and 1 N-terminal TMS.
P5 protein of the Blackberry vein banding-associated viru