Loss of gap junction plaques and inhibition of intercellular communication in ilimaquinone-treated BICR-M1R(k) and NRK cells

P. A. Feldman, J. Kim, D. W. Laird

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

To examine the mechanism(s) and pathways of gap junction formation and removal a novel and reversible inhibitor of protein secretion, ilimaquinone (IQ), was employed. IQ has been reported to cause the vesiculation of Golgi membranes, block protein transport at the cis-Golgi and depolymerize cytoplasmic microtubules. Connexin43 (Cx43) immunolabeling and dye microinjection experiments revealed that gap junction plaques were lost and intercellular communication was inhibited following IQ treatment for 1 hr in BICR-M1R(k) rat mammary tumor cells and for 2 hr in normal rat kidney (NRK) cells. Gap junction plaques and intercellular communication recovered within 2 hr when IQ was removed. IQ, however, did not affect the distribution of zonula occludens-1, a protein associated with tight junctions. Western blot analysis revealed that the IQ-induced loss of gap junction plaques was accompanied by a limited reduction in the highly phosphorylated form of Cx43, previously shown to be correlated with gap junction plaques. The presence of IQ inhibited the formation of new gap junction plaques in BICR-M1R(k) cells under conditions where preexisting gap junctions were downregulated by brefeldin A treatment. Treatment of BICRM1R(k) and NRK cells with other microtubule depolymerization agents did not inhibit plaque formation or promote rapid gap junction removal. These findings suggest that IQ disrupts intercellular communication by inhibiting the events that are involved in plaque formation and/or retention at the cell surface independent of its effects on microtubules. Our results also suggest that additional factors other than phosphorylation are necessary for Cx43 assembly into gap junction plaques.

Original languageEnglish
Pages (from-to)275-287
Number of pages13
JournalJournal of Membrane Biology
Volume155
Issue number3
DOIs
StatePublished - Jan 1 1997
Externally publishedYes

Fingerprint

Gap Junctions
Kidney
Connexin 43
Microtubules
Zonula Occludens-1 Protein
Brefeldin A
ilimaquinone
Preexisting Condition Coverage
Membrane Transport Proteins
Tight Junctions
Microinjections
Coloring Agents
Therapeutics
Down-Regulation
Western Blotting
Phosphorylation
Breast Neoplasms

Keywords

  • Connexin43
  • Gap junction plaque
  • Ilimaquinone
  • Intercellular communication

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology

Cite this

Loss of gap junction plaques and inhibition of intercellular communication in ilimaquinone-treated BICR-M1R(k) and NRK cells. / Feldman, P. A.; Kim, J.; Laird, D. W.

In: Journal of Membrane Biology, Vol. 155, No. 3, 01.01.1997, p. 275-287.

Research output: Contribution to journalArticle

@article{6142d6e41e4b4700bae5a7ecd4fc38c8,
title = "Loss of gap junction plaques and inhibition of intercellular communication in ilimaquinone-treated BICR-M1R(k) and NRK cells",
abstract = "To examine the mechanism(s) and pathways of gap junction formation and removal a novel and reversible inhibitor of protein secretion, ilimaquinone (IQ), was employed. IQ has been reported to cause the vesiculation of Golgi membranes, block protein transport at the cis-Golgi and depolymerize cytoplasmic microtubules. Connexin43 (Cx43) immunolabeling and dye microinjection experiments revealed that gap junction plaques were lost and intercellular communication was inhibited following IQ treatment for 1 hr in BICR-M1R(k) rat mammary tumor cells and for 2 hr in normal rat kidney (NRK) cells. Gap junction plaques and intercellular communication recovered within 2 hr when IQ was removed. IQ, however, did not affect the distribution of zonula occludens-1, a protein associated with tight junctions. Western blot analysis revealed that the IQ-induced loss of gap junction plaques was accompanied by a limited reduction in the highly phosphorylated form of Cx43, previously shown to be correlated with gap junction plaques. The presence of IQ inhibited the formation of new gap junction plaques in BICR-M1R(k) cells under conditions where preexisting gap junctions were downregulated by brefeldin A treatment. Treatment of BICRM1R(k) and NRK cells with other microtubule depolymerization agents did not inhibit plaque formation or promote rapid gap junction removal. These findings suggest that IQ disrupts intercellular communication by inhibiting the events that are involved in plaque formation and/or retention at the cell surface independent of its effects on microtubules. Our results also suggest that additional factors other than phosphorylation are necessary for Cx43 assembly into gap junction plaques.",
keywords = "Connexin43, Gap junction plaque, Ilimaquinone, Intercellular communication",
author = "Feldman, {P. A.} and J. Kim and Laird, {D. W.}",
year = "1997",
month = "1",
day = "1",
doi = "10.1007/s002329900180",
language = "English",
volume = "155",
pages = "275--287",
journal = "Journal of Membrane Biology",
issn = "0022-2631",
publisher = "Springer New York",
number = "3",

}

TY - JOUR

T1 - Loss of gap junction plaques and inhibition of intercellular communication in ilimaquinone-treated BICR-M1R(k) and NRK cells

AU - Feldman, P. A.

AU - Kim, J.

AU - Laird, D. W.

PY - 1997/1/1

Y1 - 1997/1/1

N2 - To examine the mechanism(s) and pathways of gap junction formation and removal a novel and reversible inhibitor of protein secretion, ilimaquinone (IQ), was employed. IQ has been reported to cause the vesiculation of Golgi membranes, block protein transport at the cis-Golgi and depolymerize cytoplasmic microtubules. Connexin43 (Cx43) immunolabeling and dye microinjection experiments revealed that gap junction plaques were lost and intercellular communication was inhibited following IQ treatment for 1 hr in BICR-M1R(k) rat mammary tumor cells and for 2 hr in normal rat kidney (NRK) cells. Gap junction plaques and intercellular communication recovered within 2 hr when IQ was removed. IQ, however, did not affect the distribution of zonula occludens-1, a protein associated with tight junctions. Western blot analysis revealed that the IQ-induced loss of gap junction plaques was accompanied by a limited reduction in the highly phosphorylated form of Cx43, previously shown to be correlated with gap junction plaques. The presence of IQ inhibited the formation of new gap junction plaques in BICR-M1R(k) cells under conditions where preexisting gap junctions were downregulated by brefeldin A treatment. Treatment of BICRM1R(k) and NRK cells with other microtubule depolymerization agents did not inhibit plaque formation or promote rapid gap junction removal. These findings suggest that IQ disrupts intercellular communication by inhibiting the events that are involved in plaque formation and/or retention at the cell surface independent of its effects on microtubules. Our results also suggest that additional factors other than phosphorylation are necessary for Cx43 assembly into gap junction plaques.

AB - To examine the mechanism(s) and pathways of gap junction formation and removal a novel and reversible inhibitor of protein secretion, ilimaquinone (IQ), was employed. IQ has been reported to cause the vesiculation of Golgi membranes, block protein transport at the cis-Golgi and depolymerize cytoplasmic microtubules. Connexin43 (Cx43) immunolabeling and dye microinjection experiments revealed that gap junction plaques were lost and intercellular communication was inhibited following IQ treatment for 1 hr in BICR-M1R(k) rat mammary tumor cells and for 2 hr in normal rat kidney (NRK) cells. Gap junction plaques and intercellular communication recovered within 2 hr when IQ was removed. IQ, however, did not affect the distribution of zonula occludens-1, a protein associated with tight junctions. Western blot analysis revealed that the IQ-induced loss of gap junction plaques was accompanied by a limited reduction in the highly phosphorylated form of Cx43, previously shown to be correlated with gap junction plaques. The presence of IQ inhibited the formation of new gap junction plaques in BICR-M1R(k) cells under conditions where preexisting gap junctions were downregulated by brefeldin A treatment. Treatment of BICRM1R(k) and NRK cells with other microtubule depolymerization agents did not inhibit plaque formation or promote rapid gap junction removal. These findings suggest that IQ disrupts intercellular communication by inhibiting the events that are involved in plaque formation and/or retention at the cell surface independent of its effects on microtubules. Our results also suggest that additional factors other than phosphorylation are necessary for Cx43 assembly into gap junction plaques.

KW - Connexin43

KW - Gap junction plaque

KW - Ilimaquinone

KW - Intercellular communication

UR - http://www.scopus.com/inward/record.url?scp=0030892617&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030892617&partnerID=8YFLogxK

U2 - 10.1007/s002329900180

DO - 10.1007/s002329900180

M3 - Article

VL - 155

SP - 275

EP - 287

JO - Journal of Membrane Biology

JF - Journal of Membrane Biology

SN - 0022-2631

IS - 3

ER -