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A novel interaction of the Golgi complex with the vimentin intermediate filament cytoskeleton.

Gao Y, Sztul E - J. Cell Biol. (2001)

Bottom Line: We show that the peripherally associated Golgi protein FTCD binds directly to vimentin subunits and to polymerized vimentin filaments in vivo and in vitro.Formation of the FTCD fibers is obligatorily coupled to vimentin assembly and does not occur in vim(-/-) cells.The FTCD-mediated regulation of vimentin IF is not a secondary effect of changes in the microtubule or the actin cytoskeletons, since those cytoskeletal systems appear unaffected by FTCD expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.

ABSTRACT
The integration of the vimentin intermediate filament (IF) cytoskeleton and cellular organelles in vivo is an incompletely understood process, and the identities of proteins participating in such events are largely unknown. Here, we show that the Golgi complex interacts with the vimentin IF cytoskeleton, and that the Golgi protein formiminotransferase cyclodeaminase (FTCD) participates in this interaction. We show that the peripherally associated Golgi protein FTCD binds directly to vimentin subunits and to polymerized vimentin filaments in vivo and in vitro. Expression of FTCD in cultured cells results in the formation of extensive FTCD-containing fibers originating from the Golgi region, and is paralleled by a dramatic rearrangements of the vimentin IF cytoskeleton in a coordinate process in which vimentin filaments and FTCD integrate into chimeric fibers. Formation of the FTCD fibers is obligatorily coupled to vimentin assembly and does not occur in vim(-/-) cells. The FTCD-mediated regulation of vimentin IF is not a secondary effect of changes in the microtubule or the actin cytoskeletons, since those cytoskeletal systems appear unaffected by FTCD expression. The assembly of the FTCD/vimentin fibers causes a coordinate change in the structure of the Golgi complex and results in Golgi fragmentation into individual elements that are tethered to the FTCD/vimentin fibers. The observed interaction of Golgi elements with vimentin filaments and the ability of FTCD to specifically interacts with both Golgi membrane and vimentin filaments and promote their association suggest that FTCD might be a candidate protein integrating the Golgi compartment with the IF cytoskeleton.

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FTCD fiber formation requires vimentin IFs. MFT-16 cells derived from a vimentin knockout mouse and lacking vimentin (vim−/−) and MFT-6 cells derived from a normal litter mate and containing vimentin (vim+) were transfected with rFTCD–pcDNA. 48 h later, cells were processed for immunofluorescence using polyclonal anti-FTCD and monoclonal antivimentin antibodies. FTCD/vimentin fibers form only in the vim+ cells, whereas FTCD remains diffusely distributed in the vim−/− cells.
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Figure 5: FTCD fiber formation requires vimentin IFs. MFT-16 cells derived from a vimentin knockout mouse and lacking vimentin (vim−/−) and MFT-6 cells derived from a normal litter mate and containing vimentin (vim+) were transfected with rFTCD–pcDNA. 48 h later, cells were processed for immunofluorescence using polyclonal anti-FTCD and monoclonal antivimentin antibodies. FTCD/vimentin fibers form only in the vim+ cells, whereas FTCD remains diffusely distributed in the vim−/− cells.

Mentions: The colocalization of FTCD and vimentin in the fibers could represent an independent assembly of FTCD and vimentin into filaments and a subsequent linking to form chimeric fibers. To explore whether the formation of the FTCD fibers can occur independently of vimentin or is obligatorily coupled to the coassembly of vimentin into the same structure, a vimentin-minus (vim−/−) cell line (MFT-16) derived from a vimentin knockout mouse (Colucci-Guyon et al. 1994; Svitkina et al. 1996; Holwell et al. 1997) was transfected with rFTCD–pcDNA, and the distribution of recombinant FTCD was analyzed. As a control, a vimentin-plus (vim+) cell line (MFT-6) derived from a normal litter mate of the knockout mouse was similarly analyzed. As shown in Fig. 5 A, recombinant FTCD appeared uniformly distributed throughout the cytoplasm and did not form fibers in the MFT-16 (vim−/−) cells. In contrast, extensive fibers were visible in the MFT-6 (vim+) control cell line (Fig. 5 B). The overall morphology of the FTCD/vimentin fibers in the MFT-6 cells was indistinguishable from those in COS-7 or NRK cells. These results indicate that the formation of the fibrous structures of FTCD is intrinsically dependent on the presence of vimentin, suggesting that FTCD and vimentin coassemble into the chimeric fibers.


A novel interaction of the Golgi complex with the vimentin intermediate filament cytoskeleton.

Gao Y, Sztul E - J. Cell Biol. (2001)

FTCD fiber formation requires vimentin IFs. MFT-16 cells derived from a vimentin knockout mouse and lacking vimentin (vim−/−) and MFT-6 cells derived from a normal litter mate and containing vimentin (vim+) were transfected with rFTCD–pcDNA. 48 h later, cells were processed for immunofluorescence using polyclonal anti-FTCD and monoclonal antivimentin antibodies. FTCD/vimentin fibers form only in the vim+ cells, whereas FTCD remains diffusely distributed in the vim−/− cells.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2198822&req=5

Figure 5: FTCD fiber formation requires vimentin IFs. MFT-16 cells derived from a vimentin knockout mouse and lacking vimentin (vim−/−) and MFT-6 cells derived from a normal litter mate and containing vimentin (vim+) were transfected with rFTCD–pcDNA. 48 h later, cells were processed for immunofluorescence using polyclonal anti-FTCD and monoclonal antivimentin antibodies. FTCD/vimentin fibers form only in the vim+ cells, whereas FTCD remains diffusely distributed in the vim−/− cells.
Mentions: The colocalization of FTCD and vimentin in the fibers could represent an independent assembly of FTCD and vimentin into filaments and a subsequent linking to form chimeric fibers. To explore whether the formation of the FTCD fibers can occur independently of vimentin or is obligatorily coupled to the coassembly of vimentin into the same structure, a vimentin-minus (vim−/−) cell line (MFT-16) derived from a vimentin knockout mouse (Colucci-Guyon et al. 1994; Svitkina et al. 1996; Holwell et al. 1997) was transfected with rFTCD–pcDNA, and the distribution of recombinant FTCD was analyzed. As a control, a vimentin-plus (vim+) cell line (MFT-6) derived from a normal litter mate of the knockout mouse was similarly analyzed. As shown in Fig. 5 A, recombinant FTCD appeared uniformly distributed throughout the cytoplasm and did not form fibers in the MFT-16 (vim−/−) cells. In contrast, extensive fibers were visible in the MFT-6 (vim+) control cell line (Fig. 5 B). The overall morphology of the FTCD/vimentin fibers in the MFT-6 cells was indistinguishable from those in COS-7 or NRK cells. These results indicate that the formation of the fibrous structures of FTCD is intrinsically dependent on the presence of vimentin, suggesting that FTCD and vimentin coassemble into the chimeric fibers.

Bottom Line: We show that the peripherally associated Golgi protein FTCD binds directly to vimentin subunits and to polymerized vimentin filaments in vivo and in vitro.Formation of the FTCD fibers is obligatorily coupled to vimentin assembly and does not occur in vim(-/-) cells.The FTCD-mediated regulation of vimentin IF is not a secondary effect of changes in the microtubule or the actin cytoskeletons, since those cytoskeletal systems appear unaffected by FTCD expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.

ABSTRACT
The integration of the vimentin intermediate filament (IF) cytoskeleton and cellular organelles in vivo is an incompletely understood process, and the identities of proteins participating in such events are largely unknown. Here, we show that the Golgi complex interacts with the vimentin IF cytoskeleton, and that the Golgi protein formiminotransferase cyclodeaminase (FTCD) participates in this interaction. We show that the peripherally associated Golgi protein FTCD binds directly to vimentin subunits and to polymerized vimentin filaments in vivo and in vitro. Expression of FTCD in cultured cells results in the formation of extensive FTCD-containing fibers originating from the Golgi region, and is paralleled by a dramatic rearrangements of the vimentin IF cytoskeleton in a coordinate process in which vimentin filaments and FTCD integrate into chimeric fibers. Formation of the FTCD fibers is obligatorily coupled to vimentin assembly and does not occur in vim(-/-) cells. The FTCD-mediated regulation of vimentin IF is not a secondary effect of changes in the microtubule or the actin cytoskeletons, since those cytoskeletal systems appear unaffected by FTCD expression. The assembly of the FTCD/vimentin fibers causes a coordinate change in the structure of the Golgi complex and results in Golgi fragmentation into individual elements that are tethered to the FTCD/vimentin fibers. The observed interaction of Golgi elements with vimentin filaments and the ability of FTCD to specifically interacts with both Golgi membrane and vimentin filaments and promote their association suggest that FTCD might be a candidate protein integrating the Golgi compartment with the IF cytoskeleton.

Show MeSH
Related in: MedlinePlus