Interaction of α-taxilin localized on intracellular components with the microtubule cytoskeleton

Cell Struct Funct. 2012;37(2):111-26. doi: 10.1247/csf.12002. Epub 2012 Jun 16.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cytoplasm / metabolism
  • Ethylmaleimide / chemistry
  • HeLa Cells
  • Humans
  • Microtubules / metabolism*
  • Protein Binding
  • Qa-SNARE Proteins / antagonists & inhibitors
  • Qa-SNARE Proteins / genetics
  • Qa-SNARE Proteins / metabolism
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Transport Vesicles / metabolism
  • Tubulin / metabolism
  • Vesicular Transport Proteins / antagonists & inhibitors
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism*

Substances

  • Qa-SNARE Proteins
  • RNA, Small Interfering
  • TXLNA protein, human
  • Tubulin
  • Vesicular Transport Proteins
  • Ethylmaleimide