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Identification of Sorting Motifs of AtβFruct4 for Trafficking from the ER to the Vacuole Through the Golgi and PVC
Author(s) -
Jung Chanjin,
Lee GilJe,
Jang Mihue,
Lee Myunghui,
Lee Junho,
Kang Hyangju,
Sohn Eun Ju,
Hwang Inhwan
Publication year - 2011
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/j.1600-0854.2011.01276.x
Subject(s) - vacuole , golgi apparatus , rab , biology , endoplasmic reticulum , microbiology and biotechnology , transport protein , cytoplasm , protein targeting , gtpase , membrane protein , biochemistry , membrane
Although much is known about the molecular mechanisms involved in transporting soluble proteins to the central vacuole, the mechanisms governing the trafficking of membrane proteins remain largely unknown. In this study, we investigated the mechanism involved in targeting the membrane protein, AtβFructosidase 4 (AtβFruct4), to the central vacuole in protoplasts. AtβFruct4 as a green fluorescent protein (GFP) fusion protein was transported as a membrane protein during transit from the endoplasmic reticulum (ER) through the Golgi apparatus and the prevacuolar compartment (PVC). The N‐terminal cytosolic domain of AtβFruct4 was sufficient for transport from the ER to the central vacuole and contained sequence motifs required for trafficking. The sequence motifs, LL and PI, were found to be critical for ER exit, while the EEE and LCPYTRL sequence motifs played roles in trafficking primarily from the trans Golgi network (TGN) to the PVC and from the PVC to the central vacuole, respectively. In addition, actin filaments and AtRabF2a, a Rab GTPase, played critical roles in vacuolar trafficking at the TGN and PVC, respectively. On the basis of these results, we propose that the vacuolar trafficking of AtβFruct4 depends on multiple sequence motifs located at the N‐terminal cytoplasmic domain that function as exit and/or sorting signals in different stages during the trafficking process.