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Sequence‐specific, Golgi‐dependent vacuolar targeting of castor bean 2S albumin
Author(s) -
Brown Joanna C.,
Jolliffe Nicholas A.,
Frigerio Lorenzo,
Roberts Lynne M.
Publication year - 2003
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2003.01913.x
Subject(s) - golgi apparatus , albumin , chemistry , microbiology and biotechnology , biochemistry , biology , endoplasmic reticulum
Summary The targeting of the castor bean ( Ricinus communis ) 2S albumin precursor has been investigated by expressing cDNA in transformed tobacco ( Nicotiana tabacum ) leaf cells and by following biosynthesis in the native tissue. Correct targeting in both tissues was accompanied by processing of the precursor. Delivery to vacuoles was sensitive to brefeldin A (BFA) treatment in both tissues and to perturbation of COPII function in tobacco, supporting the view that transport through the Golgi is required. The targeting signal for this Golgi‐dependent routing lies within the propeptide of the first heterodimer of proalbumin. This propeptide directed a normally secreted reporter protein to the vacuoles of tobacco cells in a Golgi‐dependent manner in vivo , unless a critical Leu residue was mutated, supporting the view that a sequence‐specific signal was needed to target a seed storage protein to the vacuoles of a vegetative cell.