High impact information on HAESA

• Association of RLK5 with the KI domain is dependent on phosphorylation of RLK5 and can be abolished by dephosphorylation [1].
• HAESA, an Arabidopsis leucine-rich repeat receptor kinase, controls floral organ abscission [2].
• Immunodetection, immunoprecipitation, and protein kinase activity assays reveal HAESA is a plasma membrane serine/threonine protein kinase [2].
• Histochemical analysis of transgenic plants harboring a HAESA promoter:: beta-glucuronidase reporter gene and in situ RNA hybridization experiments show HAESA expression in the abscission zones where the sepals, petals, and stamens attach to the receptacle, at the base of pedicels, and at the base of petioles where leaves attach to the stem [2].
• The reduction of function of HAESA in transgenic plants harboring an antisense construct results in delayed abscission of floral organs, and the severity of the phenotype is directly correlated with the level of HAESA protein [2].

Biological context of HAESA

• A lysine to glutamic acid substitution in the catalytic domain of RLK5 results in the catalytically inactive protein RLK5(Cat)K711E [3].
• DNA sequence analysis suggests that the RLK5 protein contains an extracellular domain that has 21 tandemly repeated leucine-rich motifs linked, via a transmembrane hydrophobic region, to a protein kinase catalytic domain that is related to the serine/threonine family of protein kinases [3].
• In protein-binding assays, OsKAPP interacted with a receptor-like protein kinase, RLK5 of Arabidopsis, but not with the protein kinase domains of the rice and maize receptor-like protein kinases Xa21 and ZmPK1, respectively [4].
• Comparisons of SLRR and its LRR consensus sequences found significant homology to the extracellular binding domains of receptor-protein kinases RLK5 and TMK1 of Arabidopsis, and some plant disease resistance genes [5].

References