title: Membrane targeting of the small myristoylated protein 2 (SMP-2) in Leishmania major.
abstract: Leishmania parasites express three highly conserved small myristoylated proteins (SMPs) that are targeted to distinct membranes. SMP-1 is exclusively found in the flagellum, depending on myristoylation and palmitoylation. In contrast, monoacylated SMP-2 and SMP-4 are localized to the flagellar pocket and plasma membrane, respectively. Here, we demonstrate that unlike SMP-4, SMP-2 resides in detergent resistant membranes, but can be readily solubilized in the presence of high concentrations of salt. We provide evidence that in detergent resistant membranes, SMP-2 forms high molecular weight complexes in vivo. Association with detergent resistant membranes was abrogated in the presence of a C-terminal tag suggesting acylation independent targeting signals. In addition, the N-terminal region of SMP-2 contains sufficient information for membrane targeting, as a GFP-chimera localizes to the flagellar pocket. Thus while the core sequences of the SMPs are highly conserved, individual members have evolved different mechanisms for their diverse membrane localization.
authors.affiliation: Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Joanne
authors.initials: J
authors.lastname: Heng
authors.forename: Eleanor C
authors.initials: EC
authors.lastname: Saunders
authors.forename: Paul R
authors.initials: PR
authors.lastname: Gooley
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: McConville
authors.forename: Thomas
authors.initials: T
authors.lastname: Naderer
authors.forename: Dedreia
authors.initials: D
authors.lastname: Tull
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018320:Leishmania major / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D008565:Membrane Proteins; D015800:Protozoan Proteins
keywords: Acylation; Detergent resistant membranes; Flagellar pocket; Parasites