Localization and trafficking of an isoform of the AtPRA1 family to the Golgi apparatus depend on both N- and C-terminal sequence motifs.
Prenylated Rab acceptors (PRAs) bind to prenylated Rab proteins and possibly aid in targeting Rabs to their respective compartments. In Arabidopsis, 19 isoforms of PRA1 have been identified and, depending upon the isoforms, they localize to the endoplasmic reticulum (ER), Golgi apparatus and endosomes. Here, we investigated the localization and trafficking of AtPRA1.B6, an isoform of the Arabidopsis PRA1 family. In colocalization experiments with various organellar markers, AtPRA1.B6 tagged with hemagglutinin (HA) at the N-terminus localized to the Golgi apparatus in protoplasts and transgenic plants. The valine residue at the C-terminal end and an EEE motif in the C-terminal cytoplasmic domain were critical for anterograde trafficking from the ER to the Golgi apparatus. The N-terminal region contained a sequence motif for retention of AtPRA1.B6 at the Golgi apparatus. In addition, anterograde trafficking of AtPRA1.B6 from the ER to the Golgi apparatus was highly sensitive to the HA:AtPRA1.B6 level. The region that contains the sequence motif for Golgi retention also conferred the abundance-dependent trafficking inhibition. On the basis of these results, we propose that AtPRA1.B6 localizes to the Golgi apparatus and its ER-to-Golgi trafficking and localization to the Golgi apparatus are regulated by multiple sequence motifs in both the C- and N-terminal cytoplasmic domains.
Division of Molecular and Life Sciences and Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea.
Chan Jin
CJ
Jung
Myoung Hui
MH
Lee
Myung Ki
MK
Min
Inhwan
I
Hwang
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D054730:Protein Interaction Domains and Motifs; D020033:Protein Isoforms; D017368:Protein Prenylation / Q000235:genetics; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011523:Protoplasts / Q000378:metabolism; D013329:Structure-Activity Relationship; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D008565:Membrane Proteins; D020033:Protein Isoforms; D020691:rab GTP-Binding Proteins