High impact information on ADK1

• Interestingly, adk1-1 does not affect gravity-induced cytoplasmic alkalinization of the root statocytes, suggesting either that ADK1 functions between cytoplasmic alkalinization and PIN3 relocalization in a linear pathway or that the pH and PIN3-relocalization responses to gravistimulation belong to distinct branches of the pathway [1].
• Adenosine kinase modulates root gravitropism and cap morphogenesis in Arabidopsis [1].
• Adenosine kinase (ADK) is a key enzyme that regulates intra- and extracellular levels of adenosine, thereby modulating methyltransferase reactions, production of polyamines and secondary compounds, and cell signaling in animals [1].
• Mutation in one of two Arabidopsis (Arabidopsis thaliana) ADK genes, ADK1, results in cap morphogenesis defects, along with alterations in root sensitivity to gravistimulation and slower kinetics of root gravitropic curvature [1].
• In support of this model, we grew Arabidopsis under a short-day photoperiod that promotes secondary cell wall development and found both ADK activity and transcript levels to increase severalfold [2].

Biological context of ADK1

• Adenosine kinase of Arabidopsis. Kinetic properties and gene expression [3].
• Here, we show that ADK is a modulator of root cap morphogenesis and gravitropism [1].
• Maintaining methylation activities during salt stress. The involvement of adenosine kinase [2].

Associations of ADK1 with chemical compounds

• The K(m) and V(max)/K(m) for the cytokinin riboside N(6)(isopentenyl) adenosine are 3 to 5 microM and 0.021 to 0.14 L min(-1) mg(-1) protein, respectively, suggesting that adenosine is the preferred substrate for both ADK isoforms [3].
• Our data are consistent with a role for ADK and the S-adenosyl-l-methionine pathway in the control of root gravitropism and cap morphogenesis [1].
• Another Gly betaine accumulator, sugar beet (Beta vulgaris), also showed salt-responsive increases in SAHH and ADK activities and protein whereas tobacco (Nicotiana tabacum) and canola (Brassica napus), which do not accumulate Gly betaine, did not show comparable changes in these enzymes [2].

References