Natriuretic peptides--a class of heterologous molecules in plants.
Immunological and physiological evidence suggests the presence of biologically active natriuretic peptide hormones (NPs) in plants. Evidence includes specific binding of rat atrial NP, [rANP (99-126)] to plant membranes and the promotion of cyclic guanosine-3',5'-monophosphate (cGMP) mediated stomatal responses. Furthermore, anti-ANP affinity purifies biologically active plant immunoreactants (irPNPs) and a biologically active Arabidopsis thaliana irPNP (AtPNP-A) has been identified. AtPNP-A belongs to a novel class of molecules that share some similarity with the cell wall loosening expansins but do not contain the carbohydrate-binding wall anchor, thus suggesting that irPNPs and ANP are heterologues. We hypothesise that irPNP-like molecules have evolved from primitive glucanase-like molecules that have been recruited to become systemically mobile modulators of homeostasis acting via the plasma membrane. Such a function is compatible with localisation in the conductive tissue and the physiological and cellular modes of action of irPNPs reported to-date.
Gehring
C A
CA
Biotechnology Department, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa. cagehring@uwc.ac.za
Irving
H R
HR
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics; D009320:Atrial Natriuretic Factor / Q000096:biosynthesis / Q000378:metabolism*; D006706:Homeostasis / Q000502:physiology; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000096:biosynthesis / Q000378:metabolism*
D029681:Arabidopsis Proteins; C464762:PNP-A protein, Arabidopsis; D010940:Plant Proteins; D009320:Atrial Natriuretic Factor