Expansion of the trans-Golgi network following activated collagen secretion is supported by a coiled-coil microtubule-bundling protein, p180, on the ER.
A coiled-coil endoplasmic reticulum (ER) protein, p180, was originally reported as a ribosome-binding receptor on the rough ER and is highly expressed in secretory tissues. Recently, we reported new functions of p180 as a microtubule-bundling protein on the ER. Here, we investigated the specific roles of p180 in the Golgi complex organization following stimulated collagen secretion. Targeted depletion of p180 by siRNA transfection caused marked reduction of TGN, while other marker levels for the cis or medial Golgi were not markedly changed. Ascorbate stimulation resulted in trans-Golgi network (TGN) expansion to the periphery in control cells that is characterized by both increased membrane amounts and extended shape. In contrast, loss of p180 resulted in retraction of the TGN regardless of ascorbate stimulation. The TGN developed to the periphery along stabilized microtubule bundles, and overexpression of MTB-1 fragment caused dominant-negative phenotypes. Once disorganized, the retracted TGN did not recover in the absence of p180 despite elevated acetylated tubulin levels. TGN46 and p180 were co-distributed in epithelial basal layer cells of human mucosal and gastrointestinal tissues. Taken together, we propose a novel function of p180-abundant ER on the TGN expansion, both of which are highly developed in various professional secretory cells.
Ueno
Tomonori
T
Nippi Research Institute of Biomatrix, Toride, Ibaraki 302-0017, Japan.
Kaneko
Keiko
K
Katano
Harutaka
H
Sato
Yuko
Y
Mazitschek
Ralph
R
Tanaka
Keisuke
K
Hattori
Shunji
S
Irie
Shinkichi
S
Sata
Tetsutaro
T
Ogawa-Goto
Kiyoko
K
D000107:Acetylation / Q000187:drug effects; D000813:Anilides / Q000494:pharmacology; D002460:Cell Line; D003094:Collagen / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D007150:Immunohistochemistry; D007700:Kinetics; D008868:Microtubule Proteins / Q000378:metabolism*; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D010641:Phenotype; D011347:Procollagen / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D021601:trans-Golgi Network / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D002352:Carrier Proteins
D000813:Anilides; D003094:Collagen; D006877:Hydroxamic Acids; D008868:Microtubule Proteins; D011347:Procollagen; D018160:Receptors, Cytoplasmic and Nuclear; C474316:tubacin; C000602809:RRBP1 protein, human; D002352:Carrier Proteins