Integrative Plant Physiology
Bandyopadhyay, Anindita , Titapiwatanakun, Boosaree , Hosein, Fazeeda , Blakeslee, Joshua , Makam, Srinivas , Peer, Wendy , Murphy, Angus .
Aminopeptidase M1 (APM1) plays a role in development in Arabidopsis.
The Arabidopsis aminopeptidase M1 family consists of four members. Arabidopsis aminopeptidase M1 (APM1) is a bifunctional protein with distinct catalytic and trafficking domains with similarity to the human insulin-responsive (IRAP) and AP-N (CD13) aminopeptidases. APM1 was originally identified in low affinity factions from chromatography utilizing the auxin efflux inhibitor NPA. Biochemical and mutant analyses indicate separate developmental roles for the catalytic and trafficking domains of APM1. apm1 mutant phenotypes can be phenocopied by high concentrations of NPA and by treatments with APN-dependent cellular trafficking inhibitors and M1 aminopeptidase enzymatic inhibitors. Loss of APM1 function resulting from mutations or inhibitor treatments alters subcellular localization of auxin transporters like PIN1, PIN2 and PGP19, reducing plasma membrane association. APM1 expression occurs in regions of differentiation, is auxin responsive and increases asymmetrically in epidermal cells of the elongation zone in gravistimulated roots. In severe apm1 alleles, embryos are developmentally arrested at the globular stage and eventually abort. In less severe alleles, some overall embryonic defects persist and root initiation occurs in the embryo, but subsequent root differentiation and development are severely impaired. Mature heterozygous apm1 mutants expressing a truncated form of the protein are dwarfs and lack shoot apical dominance consistent with observed altered auxin transport. APM1 is localized at the plasma membrane and in intracellular bodies consistent with a role in cellular trafficking similar to that seen with mammalian orthologues. Co-localization of APM1 with subcellular and trafficking markers suggests the trafficking pathways in which APM1 functions.
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aminopeptidase M1 (APM1)
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM