Interaction of α-taxilin localized on intracellular components with the microtubule cytoskeleton.
Intracellular vesicle traffic plays an essential role in the establishment and maintenance of organelle identity and biosynthetic transport. We have identified α-taxilin as a binding partner of the syntaxin family, which is involved in intracellular vesicle traffic. Recently, we have found that α-taxilin is over-expressed in malignant tissues including hepatocellular carcinoma and renal cell carcinoma. However, a precise role of α-taxilin in intracellular vesicle traffic and carcinogenesis remains unclear. Then, we first investigated here the intracellular distribution of α-taxilin in Hela cells. Immunofluorescence studies showed that α-taxilin distributes throughout the cytoplasm and exhibits a tubulo-vesicular pattern. Biochemical studies showed that α-taxilin is abundantly localized on intracellular components as a peripheral membrane protein. Moreover, we found that α-taxilin distributes in microtubule-dependent and syntaxin-independent manners, that α-taxilin directly binds to polymerized tubulin in vitro, and that N-ethylmaleimide but not brefeldin A affects the intracellular distribution of α-taxilin. These results indicate that α-taxilin is localized on intracellular components in a syntaxin-independent manner and that the α-taxilin-containing intracellular components are associated with the microtubule cytoskeleton and suggest that α-taxilin functions as a linker protein between the α-taxilin-containing intracellular components and the microtubule cytoskeleton.
Department of Molecular and Cell Biology, Graduate School of Medicine, Dokkyo Medical University, Tochigi, Japan.
Yukimi
Y
Horii
Satoru
S
Nogami
Yoji
Y
Kawano
Takako
T
Kaneko-Kawano
Natsuko
N
Ohtomo
Tomoaki
T
Tomiya
Hiromichi
H
Shirataki
D003593:Cytoplasm / Q000378:metabolism; D005033:Ethylmaleimide / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D008870:Microtubules / Q000378:metabolism*; D011485:Protein Binding; D050765:Qa-SNARE Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D022161:Transport Vesicles / Q000378:metabolism; D014404:Tubulin / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
D050765:Qa-SNARE Proteins; D034741:RNA, Small Interfering; C488100:TXLNA protein, human; D014404:Tubulin; D033921:Vesicular Transport Proteins; D005033:Ethylmaleimide