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Quantitative Analysis of Membrane Protein Transport Across the Nuclear Pore Complex
Author(s) -
Meinema Anne C.,
Poolman Bert,
Veenhoff Liesbeth M.
Publication year - 2013
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/tra.12048
Subject(s) - karyopherin , nuclear transport , nuclear pore , biology , nuclear localization sequence , microbiology and biotechnology , transport protein , linker , transmembrane protein , transmembrane domain , nucleoporin , nls , biophysics , inner membrane , membrane protein , membrane transport , cytoplasm , biochemistry , membrane , cell nucleus , operating system , receptor , computer science
Nuclear transport of the Saccharomyces cerevisiae membrane proteins Src1/Heh1 and Heh2 across the NPC is facilitated by a long intrinsically disordered linker between the nuclear localization signal ( NLS ) and the transmembrane domain. The import of reporter proteins derived from Heh2 is dependent on the FG ‐Nups in the central channel, and the linker can position the transport factor‐bound NLS in the vicinity of the FG ‐Nups in the central channel, while the transmembrane segment resides in the pore membrane. Here, we present a quantitative analysis of karyopherin‐mediated import and passive efflux of reporter proteins derived from Heh2, including data on the mobility of the reporter proteins in different membrane compartments. We show that membrane proteins with extralumenal domains up to 174 kDa , terminal to the linker and NLS , passively leak out of the nucleus via the NPC , albeit at a slow rate. We propose that also during passive efflux, the unfolded linker facilitates the passage of extralumenal domains through the central channel of the NPC .