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. 2009 Nov;4(11):1049–1058. doi: 10.4161/psb.4.11.10103

Figure 3.

Figure 3

The Arabidopsis Myotubularin homolog At3g10550: domain structure, enzyme activity and AtMTM1 transcript levels under irrigated and water deficit conditions. (A) Structure of the Arabidopsis At3g10550 protein AtMTM (top) and the human MTMR2 (bottom). Domains are as defined in Begley and Dixon;33 (B) Phosphoinositide 3′-phosphatase activity of the recombinant protein containing RID-PTP-SID domains with PtdIns3P and PtdIns3,5P2 as substrates; (C) activity of PTeN (phosphatase and tensin) assayed in parallel as a positive control; (D) Real-time RT-PcR assay of the AtMTM1 gene transcript levels in non-stressed wild type leaves and in leaves stressed by exposure to air for two hours; (E) Lineweaver-Burk curves for Ptdins3P and Ptdins3,5P2 used as substrates for atMTM: Km = 146 µM and Vmax = 0.12 nmol/min/mg for PI(3)P; Km and Vmax for PI(3,5)P2 (C8): 101 µM and 0.16 nmol/min/mg.