TY - JOUR
T1 - Subcellular Localization of Rice Acyl-CoA-Binding Proteins ACBP4 and ACBP5 Supports Their Non-redundant Roles in Lipid Metabolism
AU - Liao, Pan
AU - Leung, King Pong
AU - Lung, Shiu-Cheung
AU - Panthapulakkal Narayanan, Saritha
AU - Jiang, Liwen
AU - Chye, Mee-Len
N1 - Funding Information:
This work was supported by the Wilson and Amelia Wong Endowment Fund, Research Grants Council of Hong Kong (AoE/M-05/12) and Innovation Technology Fund of Innovation Technology Commission: Funding Support to State Key Laboratories in Hong Kong. PL was supported by a Postdoctoral Fellowship from the AoE/M-05/12 and the University of Hong Kong.
Publisher Copyright:
© 2020 Liao, Leung, Lung, Panthapulakkal Narayanan, Jiang and Chye.
PY - 2020/3/24
Y1 - 2020/3/24
N2 - Acyl-CoA-binding proteins (ACBPs), conserved at the acyl-CoA-binding
domain, can bind acyl-CoA esters as well as transport them
intracellularly. Six ACBPs co-exist in each model plant, dicot Arabidopsis thaliana (thale cress) and monocot Oryza sativa (rice). Although Arabidopsis ACBPs have been studied extensively, less is known about the rice ACBPs. OsACBP4 is highly induced by salt treatment, but down-regulated following pathogen infection, while OsACBP5
is up-regulated by both wounding and pathogen treatment. Their
differential expression patterns under various stress treatments suggest
that they may possess non-redundant functions. When expressed from the CaMV35S
promoter, OsACBP4 and OsACBP5 were subcellularly localized to different
endoplasmic reticulum (ER) domains in transgenic Arabidopsis. As these
plants were not stress-treated, it remains to be determined if OsACBP
subcellular localization would change following treatment. Given that
the subcellular localization of proteins may not be reliable if not
expressed in the native plant, this study addresses OsACBP4:GFP and OsACBP5:DsRED
expression from their native promoters to verify their subcellular
localization in transgenic rice. The results indicated that OsACBP4:GFP
was targeted to the plasma membrane besides the ER, while OsACBP5:DsRED
was localized at the apoplast, in contrast to their only localization at
the ER in transgenic Arabidopsis. Differences in tagged-protein
localization in transgenic Arabidopsis and rice imply that protein
subcellular localization studies are best investigated in the native
plant. Likely, initial targeting to the ER in a non-native plant could
not be followed up properly to the final destination(s) unless it
occurred in the native plant. Also, monocot (rice) protein targeting may
not be optimally processed in a transgenic dicot (Arabidopsis), perhaps
arising from the different processing systems for routing between them.
Furthermore, changes in the subcellular localization of OsACBP4:GFP and
OsACBP5:DsRED were not detectable following salt and pathogen
treatment, respectively. These results suggest that OsACBP4 is likely
involved in the intracellular shuttling of acyl-CoA esters and/or other
lipids between the plasma membrane and the ER, while OsACBP5 appears to
participate in the extracellular transport of acyl-CoA esters and/or
other lipids, suggesting that they are non-redundant proteins in lipid
trafficking.
AB - Acyl-CoA-binding proteins (ACBPs), conserved at the acyl-CoA-binding
domain, can bind acyl-CoA esters as well as transport them
intracellularly. Six ACBPs co-exist in each model plant, dicot Arabidopsis thaliana (thale cress) and monocot Oryza sativa (rice). Although Arabidopsis ACBPs have been studied extensively, less is known about the rice ACBPs. OsACBP4 is highly induced by salt treatment, but down-regulated following pathogen infection, while OsACBP5
is up-regulated by both wounding and pathogen treatment. Their
differential expression patterns under various stress treatments suggest
that they may possess non-redundant functions. When expressed from the CaMV35S
promoter, OsACBP4 and OsACBP5 were subcellularly localized to different
endoplasmic reticulum (ER) domains in transgenic Arabidopsis. As these
plants were not stress-treated, it remains to be determined if OsACBP
subcellular localization would change following treatment. Given that
the subcellular localization of proteins may not be reliable if not
expressed in the native plant, this study addresses OsACBP4:GFP and OsACBP5:DsRED
expression from their native promoters to verify their subcellular
localization in transgenic rice. The results indicated that OsACBP4:GFP
was targeted to the plasma membrane besides the ER, while OsACBP5:DsRED
was localized at the apoplast, in contrast to their only localization at
the ER in transgenic Arabidopsis. Differences in tagged-protein
localization in transgenic Arabidopsis and rice imply that protein
subcellular localization studies are best investigated in the native
plant. Likely, initial targeting to the ER in a non-native plant could
not be followed up properly to the final destination(s) unless it
occurred in the native plant. Also, monocot (rice) protein targeting may
not be optimally processed in a transgenic dicot (Arabidopsis), perhaps
arising from the different processing systems for routing between them.
Furthermore, changes in the subcellular localization of OsACBP4:GFP and
OsACBP5:DsRED were not detectable following salt and pathogen
treatment, respectively. These results suggest that OsACBP4 is likely
involved in the intracellular shuttling of acyl-CoA esters and/or other
lipids between the plasma membrane and the ER, while OsACBP5 appears to
participate in the extracellular transport of acyl-CoA esters and/or
other lipids, suggesting that they are non-redundant proteins in lipid
trafficking.
KW - acyl-CoA-binding protein
KW - Oryzae sativa
KW - pathogen treatment
KW - salt treatment
KW - subcellular localization
UR - http://www.scopus.com/inward/record.url?scp=85083092487&partnerID=8YFLogxK
U2 - 10.3389/fpls.2020.00331
DO - 10.3389/fpls.2020.00331
M3 - Journal article
AN - SCOPUS:85083092487
SN - 1664-462X
VL - 11
JO - Frontiers in Plant Science
JF - Frontiers in Plant Science
M1 - 331
ER -