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A key function of activated macrophages is to secrete proinflammatory cytokines such as TNFα; however, the intracellular pathway and machinery responsible for cytokine trafficking and secretion is largely undefined. Here we show that individual SNARE proteins involved in vesicle docking and fusion are regulated at both gene and protein expression upon stimulation with the bacterial cell wall component lipopolysaccharide. Focusing on two intracellular SNARE proteins, Vti1b and syntaxin 6 (Stx6), we show that they are up-regulated in conjunction with increasing cytokine secretion in activated macrophages and that their levels are selectively titrated to accommodate the volume and timing of post-Golgi cytokine trafficking. In macrophages, Vti1b and syntaxin 6 are localized on intracellular membranes and are present on isolated Golgi membranes and on Golgi-derived TNFα vesicles budded in vitro. By immunoprecipitation, we find that Vti1b and syntaxin 6 interact to form a novel intracellular Q-SNARE complex. Functional studies using overexpression of full-length and truncated proteins show that both Vti1b and syntaxin 6 function and have rate-limiting roles in TNFα trafficking and secretion. This study shows how macrophages have uniquely adapted a novel Golgi-associated SNARE complex to accommodate their requirement for increased cytokine secretion. A key function of activated macrophages is to secrete proinflammatory cytokines such as TNFα; however, the intracellular pathway and machinery responsible for cytokine trafficking and secretion is largely undefined. Here we show that individual SNARE proteins involved in vesicle docking and fusion are regulated at both gene and protein expression upon stimulation with the bacterial cell wall component lipopolysaccharide. Focusing on two intracellular SNARE proteins, Vti1b and syntaxin 6 (Stx6), we show that they are up-regulated in conjunction with increasing cytokine secretion in activated macrophages and that their levels are selectively titrated to accommodate the volume and timing of post-Golgi cytokine trafficking. In macrophages, Vti1b and syntaxin 6 are localized on intracellular membranes and are present on isolated Golgi membranes and on Golgi-derived TNFα vesicles budded in vitro. By immunoprecipitation, we find that Vti1b and syntaxin 6 interact to form a novel intracellular Q-SNARE complex. Functional studies using overexpression of full-length and truncated proteins show that both Vti1b and syntaxin 6 function and have rate-limiting roles in TNFα trafficking and secretion. This study shows how macrophages have uniquely adapted a novel Golgi-associated SNARE complex to accommodate their requirement for increased cytokine secretion. A primary function of activated macrophages is the rapid and abundant secretion of proinflammatory cytokines such as TNFα. 1The abbreviations used are: TNFα, tumor necrosis factor-α; TACE, TNFα-converting enzyme; SNARE, soluble NSF attachment protein receptors; NSF, N-ethylmaleimide-sensitive factor; LPS, lipopolysaccharide; IFNγ, interferon-γ; GFP, green fluorescent protein; GTPγS, guanosine 5′-3-O-(thio)triphosphate; Stx6, syntaxin 6; β-COP, coat protein complex β.1The abbreviations used are: TNFα, tumor necrosis factor-α; TACE, TNFα-converting enzyme; SNARE, soluble NSF attachment protein receptors; NSF, N-ethylmaleimide-sensitive factor; LPS, lipopolysaccharide; IFNγ, interferon-γ; GFP, green fluorescent protein; GTPγS, guanosine 5′-3-O-(thio)triphosphate; Stx6, syntaxin 6; β-COP, coat protein complex β. This secretion is essential to mount a successful inflammatory response but is equally the cause of severe clinical problems in acute and chronic inflammatory disease (1Palladino M.A. Bahjat F.R. Theodorakis E.A. Moldawer L.L. Nat. Rev. Drug. Discov. 2003; 2: 736-746Crossref PubMed Scopus (507) Google Scholar). The bacterial cell wall component LPS activates macrophages, eliciting the rapid synthesis of TNFα as a type II membrane precursor and subsequent proteolytic cleavage for secretion of the active cytokine (2Black R.A. Rauch C.T. Kozlosky C.J. Peschon J.J. Slack J.L. Wolfson M.F. Castner B.J. Stocking K.L. Reddy P. Srinivasan S. Nelson N. Boiani N. Schooley K.A. Gerhart M. Davis R. Fitzner J.N. Johnson R.S. Paxton R.J. March C.J. Cerretti D.P. Nature. 1997; 385: 729-733Crossref PubMed Scopus (2656) Google Scholar, 3Hume D.A. Ross I.L. Himes S.R. Sasmono R.T. Wells C.A. Ravasi T. J. Leukocyte Biol. 2002; 72: 621-627PubMed Google Scholar, 4Raabe T. Bukrinsky M. Currie R.A. J. Biol. Chem. 1998; 273: 974-980Abstract Full Text Full Text PDF PubMed Scopus (158) Google Scholar). Newly synthesized TNFα precursors accumulate in the Golgi complex (5Shurety W. Merino-Trigo A. Brown D. Hume D.A. Stow J.L. J. Interferon Cytokine Res. 2000; 20: 427-438Crossref PubMed Scopus (86) Google Scholar, 6Shurety W. Pagan J.K. Prins J.B. Stow J.L. Lab. Investig. 2001; 81: 107-117Crossref PubMed Scopus (32) Google Scholar); thereafter, little is known about the secretory pathway, the specific trafficking machinery or mechanisms that ensure the rapid delivery of cytokine to the cell surface for release. SNAREs are key regulators in all fusion events occurring in the secretory pathway (7Jahn R. Lang T. Sudhof T.C. Cell. 2003; 112: 519-533Abstract Full Text Full Text PDF PubMed Scopus (1200) Google Scholar). Vesicle docking and fusion requires a specific R-SNARE on the vesicle to bind to two or three unique receptor target molecules, the Q-SNAREs, on the target membrane to form a trans-complex, thus pulling the membranes in close proximity and overcoming the energy barrier for fusion (8Rothman J.E. Nat. Med. 2002; 8: 1059-1062Crossref PubMed Scopus (117) Google Scholar, 9Sollner T. Bennett M.K. Whiteheart S.W. Scheller R.H. Rothman J.E. Cell. 1993; 75: 409-418Abstract Full Text PDF PubMed Scopus (1564) Google Scholar). Four different conserved SNARE motifs (Qa, Qb, Qc and R) form an extended four-helix bundle and are sufficient for complex formation. Distinct complexes of SNARE family proteins are required to mediate vesicle docking and fusion on different membranes and at different vesicle trafficking steps (7Jahn R. Lang T. Sudhof T.C. Cell. 2003; 112: 519-533Abstract Full Text Full Text PDF PubMed Scopus (1200) Google Scholar, 10Parlati F. Varlamov O. Paz K. McNew J.A. Hurtado D. Sollner T.H. Rothman J.E. Proc. Natl. Acad. Sci. U. S. A. 2002; 99: 5424-5429Crossref PubMed Scopus (144) Google Scholar). The best characterized of the SNARE complexes functions in the fusion of synaptic vesicles at the plasma membrane. Intracellular SNARE complexes tend to be less well defined for a number of reasons; SNARES can participate in multiple fusion steps throughout the cell and as such can interact with different sets of SNARE partners. Additionally, differences in SNARE complexes and localization can exist between cell types. Syntaxin 6 is a promiscuous SNARE partner, implicated in multiple complexes and associated with functions in both exocytic and endocytic pathways (11Wendler F. Tooze S. Traffic. 2001; 2: 606-611Crossref PubMed Scopus (88) Google Scholar). It typically resides on membranes and vesicles in and around the trans-Golgi network (TGN). Vti1b is known in a much more restricted context, that of a single SNARE complex on late endosomes, where it has been implicated in late endosome homotypic fusion and in late endosome-lysosome fusion (12Antonin W. Holroyd C. Fasshauer D. Pabst S. Von Mollard G.F. Jahn R. EMBO J. 2000; 19: 6453-6464Crossref PubMed Scopus (211) Google Scholar, 13Pryor P.R. Mullock B.M. Bright N.A. Lindsay M.R. Gray S.R. Richardson S.C. Stewart A. James D.E. Piper R.C. Luzio J.P. EMBO Rep. 2004; 5: 590-595Crossref PubMed Scopus (187) Google Scholar). There is also evidence that it interacts with EpsinR, a protein involved in exocytic trafficking (14Chidambaram S. Mullers N. Wiederhold K. Haucke V. von Mollard G.F. J. Biol. Chem. 2004; 279: 4175-4179Abstract Full Text Full Text PDF PubMed Scopus (67) Google Scholar, 15Hirst J. Miller S.E. Taylor M.J. von Mollard G.F. Robinson M.S. Mol. Biol. Cell. 2004; 15: 5593-5602Crossref PubMed Scopus (79) Google Scholar). A number of SNARE proteins have been identified in macrophages (16Hackam D.J. Rotstein O.D. Bennett M.K. Klip A. Grinstein S. Manolson M.F. J. Immunol. 1996; 156: 4377-4383PubMed Google Scholar, 17Prekeris R. Klumperman J. Scheller R.H. Eur. J. Cell Biol. 2000; 79: 771-780Crossref PubMed Scopus (48) Google Scholar, 18Ward D.M. Pevsner J. Scullion M.A. Vaughn M. Kaplan J. Mol. Biol. Cell. 2000; 11: 2327-2333Crossref PubMed Scopus (108) Google Scholar). VAMP3 has been shown to function in the formation of phagosomes (19Bajno L. Peng X.R. Schreiber A.D. Moore H.P. Trimble W.S. Grinstein S. J. Cell Biol. 2000; 149: 697-706Crossref PubMed Scopus (259) Google Scholar), and we have shown that the Q-SNARE complex of syntaxin 4 and SNAP23, along with the sec1/Munc18 family (SM) protein Munc18c, functions at the plasma membrane and is required for TNFα secretion in macrophages (20Pagan J.K. Wylie F.G. Joseph S. Widberg C. Bryant N.J. James D.E. Stow J.L. Curr. Biol. 2003; 13: 156-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar). The majority of the molecules involved in regulating vesicle budding from the Golgi and the transport to and fusion with the target membrane remain to be identified in macrophages. Here we show that a novel Q-SNARE complex, located on similar Golgi-derived vesicles as TNFα, is up-regulated at a rate-limiting step in the secretion of TNFα to maximize cytokine secretion during inflammation. Antibodies and Reagents—Anti-mouse TNFα antibodies were purchased from Genzyme, anti-syntaxin 3 antibodies were purchased from Sapphire Biosciences, and anti-β-tubulin antibodies were purchased from Molecular Probes. Antibodies specific for VAMP2, VAMP8, Stx7, Stx8, and SNAP-23 were purchased from Synaptic Systems, whereas antibodies to Vti1A, Vti1B, Stx6, GS28, γ-adaptin, and GM130 were purchased from BD Biosciences. Antibodies to Munc-18c were a kind gift from David James (Garvan Institute of Medical Research, Sydney, Australia). Antibodies to β-COP were a kind gift from Rohan Teasdale (Institute for Molecular Bioscience, Brisbane, Australia). Cell Culture, Molecular Cloning, and Electroporation—RAW264.7 murine macrophages were cultured and activated with LPS as described previously (20Pagan J.K. Wylie F.G. Joseph S. Widberg C. Bryant N.J. James D.E. Stow J.L. Curr. Biol. 2003; 13: 156-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar). In some experiments, macrophages were incubated for 18 h in the presence of 500 pg/ml interferon-γ (IFN-γ) prior to treatment with LPS. SNARES (both full-length and truncated) were cloned into the pEGFP-C2 vector (Clontech, BD Biosciences) to produce an N-terminal GFP-tagged protein. Syntaxin 2 was subcloned from a National Institute of Aging clone (parent clone ID J0828A07). For syntaxin 2 (amino acids 4–265) PCR amplification, the following oligonucleotides were used: 5′-tatgaattcatgcgggaccggctgcccga-3′ and 5′-gaattacccgggtcatttgccaaccgacaagc-3′. Stx6 was subcloned from a Riken Fantom clone (accession number AK019106) using the following oligonucleotides: 5′-actgaattcatgtccatggaggacccctt-3′ and 5′-gcggatccctcacagcactaggaagagga-3′ or 5′-gtggatccctcactggcgccgatcactggtca-3′. Vti1B was subcloned from a NIA clone (parent clone ID L0280F09) using the following oligonucleotides: 5′-aatgaattcatggccgcctccgccgcctc-3′ and 5′-accgttcccgggtcaatggtgtcgaaagaatt-3′ or 5′-gcggatccctcacagcaacttgttggttatca-3′. Macrophages were electroporated, using Gene Pulser II (Bio-Rad), for transient expression of cDNAs using 2.5 × 107 cells with 10 μg DNA, with a high capacitance setting (280 mV and 950 microfarads). Cells were washed and typically cultured for 24 h. Microarray Analysis—RAW 264.7 macrophages, cultured in the presence of LPS (100 ng/ml) for varying times were extracted for mRNA, and microarray analysis was performed according to the protocol of Ref. 21Rowland J.E. Lichanska A.M. Kerr L.M. White M. d'Aniello E.M. Maher S.L. Brown R. Teasdale R.D. Noakes P.G. Waters M.J. Mol. Cell. Biol. 2005; 25: 66-77Crossref PubMed Scopus (125) Google Scholar. Immunoblotting, Immunoprecipitation, and Immunofluorescence Staining—Cells were washed three times with Buffer A (10 mm Tris, pH 7.4, containing 1 mm EDTA, 0.5% Triton X-100, and Complete™ protease inhibitors (Roche Applied Science)) and lysed in Buffer A by passage through a of The was at × for 10 at 4 and the was for protein protein to and by (20Pagan J.K. Wylie F.G. Joseph S. Widberg C. Bryant N.J. James D.E. Stow J.L. Curr. Biol. 2003; 13: 156-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar). For immunoprecipitation, the cell was incubated with μg of to protein for 2 h at 4 with The were washed times in Buffer A containing mm and the proteins were in was performed as previously (20Pagan J.K. Wylie F.G. Joseph S. Widberg C. Bryant N.J. James D.E. Stow J.L. Curr. Biol. 2003; 13: 156-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar). Golgi and in Vesicle Golgi membrane and subsequent budded vesicles were from cells with LPS (100 ng/ml) for 2 h by on previously K. R. P. Stow J.L. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, F.G. L. T. Brown Stow J.L. Traffic. 2003; PubMed Scopus Google Scholar). The were by and for TNFα and trafficking of TNFα from the Golgi complex to the cell surface was using an described previously (20Pagan J.K. Wylie F.G. Joseph S. Widberg C. Bryant N.J. James D.E. Stow J.L. Curr. Biol. 2003; 13: 156-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar). A BD Biosciences) was used according to the to levels of TNFα. SNARE to in activated macrophages, TNFα secretion is in the of TNFα protein synthesis at 2 h and by (5Shurety W. Merino-Trigo A. Brown D. Hume D.A. Stow J.L. J. Interferon Cytokine Res. 2000; 20: 427-438Crossref PubMed Scopus (86) Google Scholar). of the trafficking machinery of the cell that are regulated by LPS during a for proteins involved in the secretory (20Pagan J.K. Wylie F.G. Joseph S. Widberg C. Bryant N.J. James D.E. Stow J.L. Curr. Biol. 2003; 13: 156-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar). have previously shown that a plasma membrane Q-SNARE complex of syntaxin 4 and SNAP23, along with Munc18c, is up-regulated by LPS and that it functions in TNFα delivery to the cell surface (20Pagan J.K. Wylie F.G. Joseph S. Widberg C. Bryant N.J. James D.E. Stow J.L. Curr. Biol. 2003; 13: 156-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar). were used in a to for SNARE proteins in activated macrophages gene at Gene number A response to LPS by macrophages was by the of inflammatory cytokine of TNFα SNARE of were from as regulators of TNFα Stx6 and in expression at both and protein levels in response to LPS with the of TNFα The show that Stx6 is regulated at the gene whereas the in Vti1b protein at the gene some of macrophages with by with LPS more TNFα and secrete more TNFα cells activated with LPS (5Shurety W. Merino-Trigo A. Brown D. Hume D.A. Stow J.L. J. Interferon Cytokine Res. 2000; 20: 427-438Crossref PubMed Scopus (86) Google in is more TNFα and it is to the cell surface in macrophages were to produce an in Stx6 and Vti1b protein levels and in macrophages, Stx6 and Vti1b are regulated by the pathways as TNFα, and they are both up-regulated to the for TNFα trafficking. Stx6 and Vti1B at the Golgi and of the SNARE to Stx6 and Vti1b were used to the proteins in macrophages. Stx6 was on the Golgi complex, where it with synthesized TNFα and in vesicles of Vti1b was associated with the Golgi complex, also with TNFα, whereas Vti1b was on The that both Stx6 and Vti1b are associated with the Golgi complex that both have a in the secretory the of SNARE complexes in activated macrophages two a complex of three Q-SNARE and and R-SNARE D. Jahn R. Proc. Natl. Acad. Sci. U. S. A. 1998; PubMed Scopus Google Scholar). from activated shows that in Vti1b is of at two SNARE complexes In the Vti1b is to complex with known SNARE proteins and In the a novel complex, with Stx6 and A R-SNARE for the complex at is and are involved in novel complex in macrophages SNARE was also to be in macrophages, and it complexes with Stx6 but with Vti1b as by the of the and SNARE complex. complexes were also from macrophages Vti1b and Stx6 are of a novel SNARE complex. that Vti1b and Stx6 were both present in the Golgi is a for their and Stx6 and Vti1B on Golgi-derived to the of Vti1B and Stx6 with the Golgi complex and secretory pathway in a was isolated a Golgi from of macrophages. Vti1B and Stx6 in Golgi Golgi membranes were incubated in in the presence of and to the budding of membrane we have previously to the of a of Golgi-derived vesicles that can be by analysis K. R. P. Stow J.L. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, F.G. L. T. Brown Stow J.L. Traffic. 2003; PubMed Scopus Google Scholar). Vti1B and Stx6 were on Golgi membranes and in the containing budded vesicles or membranes were on a vesicle budding was by the membrane of the protein β-COP and the presence of in different Vti1B and Stx6 were on a of membrane budding the both in the as TNFα show that Vti1B and Stx6 are both associated with containing TNFα that from the Golgi complex. both SNARE proteins are in a to Vti1B and Stx6 in the Vti1B and Stx6 are up-regulated in activated macrophages, form a SNARE complex, and are in similar Golgi-derived to the TNFα, studies were performed to Vti1B and Stx6 in the exocytic pathway in macrophages. of full-length SNARE proteins is known to their function (20Pagan J.K. Wylie F.G. Joseph S. Widberg C. Bryant N.J. James D.E. Stow J.L. Curr. Biol. 2003; 13: 156-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar, S. K. J.E. J. Biol. Chem. 1998; 273: Full Text Full Text PDF PubMed Scopus Google Scholar), whereas overexpression of the of proteins is known to as complex formation and vesicle docking and The of GFP-tagged full-length Stx6 and Vti1b the proteins 4 and cells were by to TNFα secretion into the (5Shurety W. Merino-Trigo A. Brown D. Hume D.A. Stow J.L. J. Interferon Cytokine Res. 2000; 20: 427-438Crossref PubMed Scopus (86) Google and by to the on transport of TNFα from the Golgi complex to the cell surface (20Pagan J.K. Wylie F.G. Joseph S. Widberg C. Bryant N.J. James D.E. Stow J.L. Curr. Biol. 2003; 13: 156-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar). A in TNFα into the was from cells This with an in TNFα trafficking to the cell as increased cell surface of TNFα, in cells full-length GFP-tagged as with cells on surface delivery was in cells the of Vti1b acids cell surface delivery of TNFα in the majority of cells of macrophages that TNFα was at the of the Golgi complex, that post-Golgi but been Syntaxin 2 a in TNFα secretion (20Pagan J.K. Wylie F.G. Joseph S. Widberg C. Bryant N.J. James D.E. Stow J.L. Curr. Biol. 2003; 13: 156-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar), and overexpression of on TNFα surface delivery as a by we for the a for Vti1b in the exocytic trafficking expression is rate-limiting increasing the levels of Vti1b the of TNFα. The expression and function of Stx6 was A in TNFα into the was in GFP-tagged Stx6 as with of full-length an in TNFα surface in cells as with cells In the of Stx6 acids was in activated macrophages, cell surface TNFα was in the majority of cells as with cells by we that Vti1B and Stx6 function in the post-Golgi secretory trafficking of TNFα to the cell surface in activated macrophages. expression is also rate-limiting increasing the levels of Stx6 at the of the Golgi the of functions in TNFα secretion. macrophages or were with LPS for 2 TNFα in the was using an The of three are shown in the along with S.E. TNFα secretion is increased in cells as with cells were with LPS for 2 h in the presence of and to surface TNFα, was on cells as with cells were in of three different increased surface TNFα on cells the of and Stx6 to were with LPS in the presence of for 2 h and for surface TNFα. cells were in of three experiments, and the are shown in the along with S.E. and the of little on surface TNFα whereas the Stx6 surface TNFα show a and a novel SNARE complex involved in the of the secretory pathway in activated macrophages, cells with increased to vesicle at the of the for post-Golgi transport of In SNARE complexes on secretory mediate regulated for the complex on D. A.M. Whiteheart S.W. 2000; PubMed Google and the complex on M.R. P. R. J. Immunol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). In macrophages, cytokines are for in but be upon cell and in a of the show that key SNAREs at the of the with the cell surface SNARE complex (20Pagan J.K. Wylie F.G. Joseph S. Widberg C. Bryant N.J. James D.E. Stow J.L. Curr. Biol. 2003; 13: 156-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google are rate-limiting for cytokine secretion. SNAREs at both of the secretory pathway is thus a and essential to have shown that the intracellular Stx6 and Vti1b are regulated by the pathways as TNFα and that they are both up-regulated to the for TNFα trafficking. The rapid in protein levels that SNAREs be regulated by mechanisms as well as at a as is TNFα W. Pagan J.K. Prins J.B. Stow J.L. Lab. Investig. 2001; 81: 107-117Crossref PubMed Scopus (32) Google Scholar, P. K. N. J. Leukocyte Biol. 2004; PubMed Scopus Google Scholar). with (20Pagan J.K. Wylie F.G. Joseph S. Widberg C. Bryant N.J. James D.E. Stow J.L. Curr. Biol. 2003; 13: 156-160Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar), it that multiple SNARE proteins are to regulated expression during is known about the of SNARE expression in study in that the expression of SNARE proteins during cell with formation and trafficking N. Bryant N.J. L.M. R.J. Luzio J.P. Piper R.C. James D.E. J. Biol. Chem. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). overexpression of protein TNFα surface delivery and and the timing of expression of the proteins in macrophages to be to the timing and of TNFα trafficking in activated macrophages. Vti1b and Stx6 function TNFα in the Golgi complex, that both are required for a step in post-Golgi This is the described for Vti1b in an exocytic The similar by Stx6 or Vti1b are with the two proteins as of the complex in the secretory By immunoprecipitation, Stx6 and Vti1b along with were to form a novel Q-SNARE complex. A of with Stx6 and Vti1b SNARE proteins in has previously been N. Bryant N.J. L.M. R.J. Luzio J.P. Piper R.C. James D.E. J. Biol. Chem. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). Vti1b and Stx6 at the of the where they are associated with the Golgi-derived as the TNFα. The for is in the of TNFα at the a in regulating membrane to the for formation. studies It is that trafficking proteins such as the SNAREs functions in the cell and as such are Here we show that individual SNARE proteins are regulated to functions in the Macrophages are unique in their for secretion of The in the trafficking machinery we to how macrophages accommodate essential SNARE complexes vesicle fusion required for the transport of cytokine from the Golgi to the cell a that is to the response but with in inflammatory disease (1Palladino M.A. Bahjat F.R. Theodorakis E.A. Moldawer L.L. Nat. Rev. Drug. Discov. 2003; 2: 736-746Crossref PubMed Scopus (507) Google Scholar). a to the that macrophages have uniquely adapted their trafficking pathways to roles in the and the of by the to membrane to the plasma membrane for and to to S. C. O. J. J.J. M. Cell. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar, M. S. S. A. M.F. P. D. M. Nature. 2003; PubMed Scopus Google Scholar). studies an that also membrane in in post-Golgi pathways to macrophages to A. J. S. and D. Brown for and to all of the Stow for
Murray et al. (Sat,) studied this question.