Proteomic identification of annexins, calcium-dependent membrane binding proteins that mediate osmotic stress and abscisic acid signal transduction in Arabidopsis.
Comparative proteomic analysis of the Arabidopsis thaliana root microsomal fraction was performed to identify novel components of salt stress signaling. Among the salt-responsive microsomal proteins, two spots that increased upon salt treatment on a two-dimensional gel were identified as the same protein, designated annexin 1 (AnnAt1). Annexins comprise a multigene family of Ca2+-dependent membrane binding proteins and have been extensively studied in animal cells. AnnAt1 is strongly expressed in root but rarely in flower tissue. In this study, the results suggest that salt stress induces translocation from the cytosol to the membrane and potential turnover of existing protein. This process is blocked by EGTA treatment, implying that AnnAt1 functions in stress response are tightly associated with Ca2+. T-DNA insertion mutants of annAt1 and a different isoform, annAt4, displayed hypersensitivity to osmotic stress and abscisic acid (ABA) during germination and early seedling growth. The results collectively suggest that AnnAt1 and AnnAt4 play important roles in osmotic stress and ABA signaling in a Ca2+-dependent manner.
Lee
Sumin
S
Kumho Life and Environmental Science Laboratory, Gwangju 500-712, Korea.
Lee
Eun Jung
EJ
Yang
Eun Ju
EJ
Lee
Ji Eun
JE
Park
Ae Ran
AR
Song
Won Hyun
WH
Park
Ohkmae K
OK
D000040:Abscisic Acid / Q000494:pharmacology*; D017302:Annexins / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D004533:Egtazic Acid / Q000494:pharmacology; D015180:Electrophoresis, Gel, Two-Dimensional; D018506:Gene Expression Regulation, Plant; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism; D016254:Mutagenesis, Insertional / Q000235:genetics; D009154:Mutation / Q000235:genetics; D009997:Osmotic Pressure / Q000187:drug effects; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D040901:Proteomics; D015398:Signal Transduction / Q000187:drug effects*; D012965:Sodium Chloride / Q000494:pharmacology
D017302:Annexins; D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; C036483:T-DNA; D012965:Sodium Chloride; D004533:Egtazic Acid; D000040:Abscisic Acid; D002118:Calcium