@article{785d19be67054f939d2e8e92cf62b1d8,
title = "Expression of novel “LOCGEF” isoforms of ARHGEF18 in eosinophils",
abstract = "Genomic, transcriptomic and proteomic databases indicate that the N-terminal 322 residues encoded by the presumptive LOC100996504 gene, which is adjacent to the ARHGEF18 guanine nucleotide exchange factor gene on chromosome 19, constitute the N-terminal portion of a 1361-residue isoform of ARHGEF18, dubbed LOCGEF-X3. LOCGEF-X3 arises from the use of a leukocyte-specific alternative transcriptional start site and splicing that bypasses the initial noncoding exon of the canonical 1015-residue ARHGEF18 isoform, p114. Eosinophil LOCGEF-X3 was amplified and cloned, recombinant LOCGEF-X3 was expressed, and anti-ARHGEF18 antibody was found to recognize a band in immunoblots of eosinophil lysates that co-migrates with recombinant LOCGEF-X3. PCR of eosinophils revealed minor amounts of transcripts for X4 and X5 isoforms of LOCGEF that arise from differential splicing and differ from the X3 isoform at their extreme N-termini. No p114 transcript or protein band was detected in eosinophils. Immunostaining with anti-ARHGEF18 antibody revealed relocalization of LOCGEF and RHOA from the periphery of round unstimulated eosinophils to the 2 poles of eosinophils polarized by treatment with IL5, CCL11, or IL33 in suspension. Canonical p114 ARHGEF18 has been implicated in maintenance of epithelial cell polarity. We suggest that the “LOC” portion of LOCGEF, which is unlike any other protein domain, has unique functions in control of polarity in activated eosinophils and other leukocytes.",
keywords = "ARHGEF18, LOC100996504, alternative transcriptional start, granulocyte, guanine nucleotide exchange factor, p114-GEF",
author = "Turton, {Keren B.} and Wilkerson, {Emily M.} and Hebert, {Alex S.} and Fogerty, {Frances J.} and Schira, {Hazel M.} and Botros, {Fady E.} and Coon, {Joshua J.} and Mosher, {Deane F.}",
note = "Funding Information: The authors have been supported by National Institute of Health grants P01 HL088594 (Nizar Jarjour, PI) and R01 AI125390 (Deane Mosher and Josh Coon, co-PIs). Emily Wilkerson received training grant support from T32 HL007899. We used the Biochemistry Optical Core at UW-Madison, and are grateful to Elle Grevstad for her assistance. We thank Doug Annis for help with molecular biology and protein chemistry. Mats Johansson, Doug Annis, and Valeriu Bortnov provided useful comments on the manuscript. Finally, we thank Zhong-Jian Shen for providing cDNA from mouse eosinophils. Funding Information: K.B.T. was associated with conception, design, experiments, data analysis, and manuscript writing; E.M.W. designed the experiment, performed experiments, data analysis, and manuscript writing; A.S.H. performed data analysis; F.J.F. designed the experiment and performed experiments and data analysis; H.M.S. designed the experiment and performed experiments and data analysis; F.E.B. designed the experiment and performed experiments and data analysis; J.J.C. was involved in conception, design, and data analysis; and D.F.M. was involved in conception, design, data analysis, and manuscript writing. The authors have been supported by National Institute of Health grants P01 HL088594 (Nizar Jarjour, PI) and R01 AI125390 (Deane Mosher and Josh Coon, co-PIs). Emily Wilkerson received training grant support from T32 HL007899. We used the Biochemistry Optical Core at UW-Madison, and are grateful to Elle Grevstad for her assistance. We thank Doug Annis for help with molecular biology and protein chemistry. Mats Johansson, Doug Annis, and Valeriu Bortnov provided useful comments on the manuscript. Finally, we thank Zhong-Jian Shen for providing cDNA from mouse eosinophils. Publisher Copyright: {\textcopyright}2018 Society for Leukocyte Biology",
year = "2018",
month = jul,
doi = "10.1002/JLB.2MA1017-418RR",
language = "English",
volume = "104",
pages = "135--145",
journal = "Journal of Leukocyte Biology",
issn = "0741-5400",
number = "1",
}