Proteolytically cleaved MLL subunits are susceptible to distinct degradation pathways

Akihiko Yokoyama, Francesca Ficara, Mark J. Murphy, Christian Meisel, Alpana Naresh, Issay Kitabayashi, Michael L. Cleary

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

The mixed lineage leukemia (MLL) proto-oncogenic protein is a histone-lysine N-methyltransferase that is produced by proteolytic cleavage and self-association of the respective functionally distinct subunits (MLL N and MLL C) to form a holocomplex involved in epigenetic transcriptional regulation. On the basis of studies in Drosophila it has been suggested that the separated subunits might also have distinct functions. In this study, we used a genetically engineered mouse line that lacked MLL C to show that the MLL N-MLL C holocomplex is responsible for MLL functions in various developmental processes. The stability of MLL N is dependent on its intramolecular interaction with MLL C, which is mediated through the first and fourth plant homeodomain (PHD) fingers (PHD1 and PHD4) and the phenylalanine/tyrosine-rich (FYRN) domain of MLL N. Free MLL N is destroyed by a mechanism that targets the FYRN domain, whereas free MLL C is exported to the cytoplasm and degraded by the proteasome. PHD1 is encoded by an alternatively spliced exon that is occasionally deleted in T-cell leukemia, and its absence produces an MLL mutant protein that is deficient for holocomplex formation. Therefore, this should be a loss-of-function mutant allele, suggesting that the known tumor suppression role of MLL may also apply to the T-cell lineage. Our data demonstrate that the dissociated MLL subunits are subjected to distinct degradation pathways and thus not likely to have separate functions unless the degradation mechanisms are inhibited.

Original languageEnglish
Pages (from-to)2208-2219
Number of pages12
JournalJournal of Cell Science
Volume124
Issue number13
DOIs
Publication statusPublished - Jul 1 2011

Fingerprint

Leukemia
Myeloid-Lymphoid Leukemia Protein
Histone-Lysine N-Methyltransferase
T-Cell Leukemia
Cell Lineage
Proteasome Endopeptidase Complex
Mutant Proteins
Phenylalanine
Epigenomics
Drosophila
Tyrosine
Exons
Cytoplasm
Alleles
T-Lymphocytes

Keywords

  • Degradation
  • MLL
  • Proteolysis

ASJC Scopus subject areas

  • Cell Biology

Cite this

Yokoyama, A., Ficara, F., Murphy, M. J., Meisel, C., Naresh, A., Kitabayashi, I., & Cleary, M. L. (2011). Proteolytically cleaved MLL subunits are susceptible to distinct degradation pathways. Journal of Cell Science, 124(13), 2208-2219. https://doi.org/10.1242/jcs.080523

Proteolytically cleaved MLL subunits are susceptible to distinct degradation pathways. / Yokoyama, Akihiko; Ficara, Francesca; Murphy, Mark J.; Meisel, Christian; Naresh, Alpana; Kitabayashi, Issay; Cleary, Michael L.

In: Journal of Cell Science, Vol. 124, No. 13, 01.07.2011, p. 2208-2219.

Research output: Contribution to journalArticle

Yokoyama, A, Ficara, F, Murphy, MJ, Meisel, C, Naresh, A, Kitabayashi, I & Cleary, ML 2011, 'Proteolytically cleaved MLL subunits are susceptible to distinct degradation pathways', Journal of Cell Science, vol. 124, no. 13, pp. 2208-2219. https://doi.org/10.1242/jcs.080523
Yokoyama, Akihiko ; Ficara, Francesca ; Murphy, Mark J. ; Meisel, Christian ; Naresh, Alpana ; Kitabayashi, Issay ; Cleary, Michael L. / Proteolytically cleaved MLL subunits are susceptible to distinct degradation pathways. In: Journal of Cell Science. 2011 ; Vol. 124, No. 13. pp. 2208-2219.
@article{115a039377674b86a194fdb848314cc0,
title = "Proteolytically cleaved MLL subunits are susceptible to distinct degradation pathways",
abstract = "The mixed lineage leukemia (MLL) proto-oncogenic protein is a histone-lysine N-methyltransferase that is produced by proteolytic cleavage and self-association of the respective functionally distinct subunits (MLL N and MLL C) to form a holocomplex involved in epigenetic transcriptional regulation. On the basis of studies in Drosophila it has been suggested that the separated subunits might also have distinct functions. In this study, we used a genetically engineered mouse line that lacked MLL C to show that the MLL N-MLL C holocomplex is responsible for MLL functions in various developmental processes. The stability of MLL N is dependent on its intramolecular interaction with MLL C, which is mediated through the first and fourth plant homeodomain (PHD) fingers (PHD1 and PHD4) and the phenylalanine/tyrosine-rich (FYRN) domain of MLL N. Free MLL N is destroyed by a mechanism that targets the FYRN domain, whereas free MLL C is exported to the cytoplasm and degraded by the proteasome. PHD1 is encoded by an alternatively spliced exon that is occasionally deleted in T-cell leukemia, and its absence produces an MLL mutant protein that is deficient for holocomplex formation. Therefore, this should be a loss-of-function mutant allele, suggesting that the known tumor suppression role of MLL may also apply to the T-cell lineage. Our data demonstrate that the dissociated MLL subunits are subjected to distinct degradation pathways and thus not likely to have separate functions unless the degradation mechanisms are inhibited.",
keywords = "Degradation, MLL, Proteolysis",
author = "Akihiko Yokoyama and Francesca Ficara and Murphy, {Mark J.} and Christian Meisel and Alpana Naresh and Issay Kitabayashi and Cleary, {Michael L.}",
year = "2011",
month = "7",
day = "1",
doi = "10.1242/jcs.080523",
language = "English",
volume = "124",
pages = "2208--2219",
journal = "Journal of Cell Science",
issn = "0021-9533",
publisher = "Company of Biologists Ltd",
number = "13",

}

TY - JOUR

T1 - Proteolytically cleaved MLL subunits are susceptible to distinct degradation pathways

AU - Yokoyama, Akihiko

AU - Ficara, Francesca

AU - Murphy, Mark J.

AU - Meisel, Christian

AU - Naresh, Alpana

AU - Kitabayashi, Issay

AU - Cleary, Michael L.

PY - 2011/7/1

Y1 - 2011/7/1

N2 - The mixed lineage leukemia (MLL) proto-oncogenic protein is a histone-lysine N-methyltransferase that is produced by proteolytic cleavage and self-association of the respective functionally distinct subunits (MLL N and MLL C) to form a holocomplex involved in epigenetic transcriptional regulation. On the basis of studies in Drosophila it has been suggested that the separated subunits might also have distinct functions. In this study, we used a genetically engineered mouse line that lacked MLL C to show that the MLL N-MLL C holocomplex is responsible for MLL functions in various developmental processes. The stability of MLL N is dependent on its intramolecular interaction with MLL C, which is mediated through the first and fourth plant homeodomain (PHD) fingers (PHD1 and PHD4) and the phenylalanine/tyrosine-rich (FYRN) domain of MLL N. Free MLL N is destroyed by a mechanism that targets the FYRN domain, whereas free MLL C is exported to the cytoplasm and degraded by the proteasome. PHD1 is encoded by an alternatively spliced exon that is occasionally deleted in T-cell leukemia, and its absence produces an MLL mutant protein that is deficient for holocomplex formation. Therefore, this should be a loss-of-function mutant allele, suggesting that the known tumor suppression role of MLL may also apply to the T-cell lineage. Our data demonstrate that the dissociated MLL subunits are subjected to distinct degradation pathways and thus not likely to have separate functions unless the degradation mechanisms are inhibited.

AB - The mixed lineage leukemia (MLL) proto-oncogenic protein is a histone-lysine N-methyltransferase that is produced by proteolytic cleavage and self-association of the respective functionally distinct subunits (MLL N and MLL C) to form a holocomplex involved in epigenetic transcriptional regulation. On the basis of studies in Drosophila it has been suggested that the separated subunits might also have distinct functions. In this study, we used a genetically engineered mouse line that lacked MLL C to show that the MLL N-MLL C holocomplex is responsible for MLL functions in various developmental processes. The stability of MLL N is dependent on its intramolecular interaction with MLL C, which is mediated through the first and fourth plant homeodomain (PHD) fingers (PHD1 and PHD4) and the phenylalanine/tyrosine-rich (FYRN) domain of MLL N. Free MLL N is destroyed by a mechanism that targets the FYRN domain, whereas free MLL C is exported to the cytoplasm and degraded by the proteasome. PHD1 is encoded by an alternatively spliced exon that is occasionally deleted in T-cell leukemia, and its absence produces an MLL mutant protein that is deficient for holocomplex formation. Therefore, this should be a loss-of-function mutant allele, suggesting that the known tumor suppression role of MLL may also apply to the T-cell lineage. Our data demonstrate that the dissociated MLL subunits are subjected to distinct degradation pathways and thus not likely to have separate functions unless the degradation mechanisms are inhibited.

KW - Degradation

KW - MLL

KW - Proteolysis

UR - http://www.scopus.com/inward/record.url?scp=79960303005&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79960303005&partnerID=8YFLogxK

U2 - 10.1242/jcs.080523

DO - 10.1242/jcs.080523

M3 - Article

VL - 124

SP - 2208

EP - 2219

JO - Journal of Cell Science

JF - Journal of Cell Science

SN - 0021-9533

IS - 13

ER -