Hosein, Fazeeda , Anindita, Bandyopadhyay , Peer, Wendy , Murphy, Angus .
Functional analysis of the membrane associated protein, APM1.
M1 aminopeptidases have been shown to cleave peptides and proteins from the N-terminal. They have been implicated in a variety of roles including embryo development and trafficking of proteins. Members of this subfamily (IRAP and APN) have been shown to have dual functions, enzymatic and trafficking. In plants, M1 aminopeptidases (MPA1 and APM1) have been shown to play a role in embryo development. AtAPM1 is a single gene that encodes a 103kDa transmembrane aminopeptidase with functionally distinct membrane trafficking and catalytic domains, like IRAP and APN. It is a structural and functional homolog of IRAP, which mediates rapid cycling of mammalian plasma membrane transport proteins whereas APN is involved in sterol trafficking from the plasma membrane and its trafficking domain has been identified as the target for the cholesterol uptake inhibitor Ezetimibe. apm mutants exhibit pleiotropic effects and include root developmental defects, which have been identified in early embryo development. These defects can be linked to the dual functional nature of APM1, as illustrated by the developmental defects of the apm mutants. Inhibitor studies with Ezetimide and PAQ-22 which targets the catalytic domain of APM1, revealed that the enzymatic activity of APM1 is distinct from its trafficking function. To further determine what roles each functional domain plays, mutational and deletion analyses will be used to determine complementation of phenotype based on function. APM1 belongs to the M1 type metallopeptidase which are type II integral membrane proteins. Structural analyses of APM1 by various computer prediction programs reveal at least one transmembrane domain is present. To determine which of the analyses is correct, the topology of APM1 will be experimentally determined.
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1 - Purdue University, HLA, 170 S. University St, WSLR Room 129, West Lafayette, IN, 47906, USA
2 - Purdue University, HLA
3 - Purdue University
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM