THESIS
2018
x, 57, that is, xii, 57 pages : illustrations (some color) ; 30 cm
Abstract
It is well known that the localizations of Arf family proteins are determined by their
corresponding guanine nucleotide exchange factors (GEFs). But even though the GEFs can
interact with the switch domains of Arf proteins, the amphipathic motifs at the N terminus of
Arf proteins are also important for their specific intracellular localizations. Here, we analyzed
the functional roles of the amphipathic motifs of the Golgi-localized Arf proteins, Arfrp1, the
endoplasmic reticulum-localized Arf protein, Sar1A and the endosome- and plasma
membrane-localized Arf protein, Arl14. We found that deleting the amphipathic helix of all of
these selected Arf proteins causes dispersal of these Arf proteins from membranes, suggesting
that the amphipathic helixes of these Arf proteins are vita...[
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It is well known that the localizations of Arf family proteins are determined by their
corresponding guanine nucleotide exchange factors (GEFs). But even though the GEFs can
interact with the switch domains of Arf proteins, the amphipathic motifs at the N terminus of
Arf proteins are also important for their specific intracellular localizations. Here, we analyzed
the functional roles of the amphipathic motifs of the Golgi-localized Arf proteins, Arfrp1, the
endoplasmic reticulum-localized Arf protein, Sar1A and the endosome- and plasma
membrane-localized Arf protein, Arl14. We found that deleting the amphipathic helix of all of
these selected Arf proteins causes dispersal of these Arf proteins from membranes, suggesting
that the amphipathic helixes of these Arf proteins are vital to their localizations. In addition,
we found that the amphipathic helix of Arfrp1, Arl14 or Sar1A is sufficient to bring cytosolic
proteins to the Golgi, the endosomes or the ER respectively. The spatial determination
mediated by Arfrp1 helix and Arl14 helix requires the acetylation modification on Arfrp1
helix and the myristoylation modification on Arl14 helix. Furthermore, we found that
Annexin A2 interacts with Arl14 and contributes to the localization of Arl14. In sum, our
results demonstrate the amphipathic motifs of Arfrp1, Arl14 and Sar1A are required and
sufficient for determining specific intracellular localizations.
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