Abstract
Proper spatiotemporal regulation of protein phosphorylation in cells and tissues is required for normal development and homeostasis. We present the protocol 'In Gel Kinase Assay', which is useful for protein kinase activity measurements from crude protein extracts. We have successfully used 'In Gel Kinase Assay' protocol to show that the Arabidopsis thaliana sextuple mutant in the PYRABACTIN RESISTANCE1/PYR1-LIKE/REGULATORY COMPONENTS OF ABA RECEPTORS (PYR/PYL/RCAR-ABA receptors; line pyr/pyl112458) is impaired in ABA-mediated activation of SnRK2.2, SnRK2.3 and OST1/SnRK2.6, as much as the triple mutant snrk2.2/2.3/2.6 (Gonzalez-Guzman et al., 2012).