Clusters of VIP-36-positive vesicles between endoplasmic reticulum and Golgi apparatus in GH3 cells.
The vesicular integral membrane protein VIP36 belongs to the family of animal lectins and may act as a cargo receptor trafficking certain glycoproteins in the secretory pathway. Immunoelectron microscopy of GH3 cells provided evidence that endogenous VIP36 is localized mainly in 70-100-nm-diameter uncoated transport vesicles between the exit site on the ER and the neighboring cis-Golgi cisterna. The thyrotrophin-releasing hormone (TRH) stimulation and treatment with actin filament-perturbing agents, cytochalasin D or B or latrunculin-B, caused marked aggregation of the VIP36-positive vesicles and the appearance of a VIP36-positive clustering structure located near the cis-Golgi cisterna. The size of this structure, which comprised conspicuous clusters of VIP36, depended on the TRH concentration. Confocal laser scanning microscopy confirmed the electron microscopically demonstrated distribution and redistribution of VIP36 in these cells. Furthermore, VIP36 colocalized with filamentous actin in the paranuclear Golgi area and its vicinity. This is the first study to show the ultrastructural distribution of VIP36 in the early secretory pathway in GH3 cells. It suggests that actin filaments are involved in glycoprotein transport between the ER and cis-Golgi cisterna by using the lectin VIP36.
Shimada
Osamu
O
Department of Anatomy, Yamanashi University School of Medicine, 1110 Tamaho-cho, Yamanashi 409-3898, Japan. oshimada@swallow.res.yamanashi-med.ac.jp
Hara-Kuge
Sayuri
S
Yamashita
Katsuko
K
Tosaka-Shimada
Hisami
H
Yanchao
Li
L
Yongnan
Li
L
Atsumi
Saoko
S
Ishikawa
Harunori
H
D000818:Animals; D045744:Cell Line, Tumor; D003571:Cytochalasin B / Q000378:metabolism; D015638:Cytochalasin D / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D037241:Mannose-Binding Lectins / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D019384:Nucleic Acid Synthesis Inhibitors / Q000378:metabolism; D051381:Rats; D013973:Thyrotropin-Releasing Hormone / Q000378:metabolism; D022161:Transport Vesicles / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure
D003598:Cytoskeletal Proteins; D037241:Mannose-Binding Lectins; D026901:Membrane Transport Proteins; D019384:Nucleic Acid Synthesis Inhibitors; D015638:Cytochalasin D; D003571:Cytochalasin B; D013973:Thyrotropin-Releasing Hormone