Involvement of the tubulin tyrosine ligase-like family member 4 polyglutamylase in PELP1 polyglutamylation and chromatin remodeling in pancreatic cancer cells.
Polyglutamylation is a new class of posttranslational modification in which glutamate side chains are formed in proteins, although its biological significance is not well known. Through our genome-wide gene expression profile analyses of pancreatic ductal adenocarcinoma (PDAC) cells, we identified the overexpression of tubulin tyrosine ligase-like family member 4 (TTLL4) in PDAC cells. Subsequent reverse transcription-PCR and Northern blot analyses confirmed its upregulation in several PDACs. TTLL4 belongs to the TTLL family which was reported to have polyglutamylase activity. Knockdown of TTLL4 by short hairpin RNA in PDAC cells attenuated the growth of PDAC cells and exogenous introduction of TTLL4 enhanced cell growth. We also found that TTLL4 expression was correlated with polyglutamylation levels of a glutamate stretch region of the proline, glutamate, and leucine-rich protein 1 (PELP1) that was shown to interact with various proteins such as histone H3, and was involved in several signaling pathways through its function as a scaffold protein. PELP1 polyglutamylation could influence its interaction with histone H3 and affect histone H3 acetylation. We also identified the interaction of PELP1 with LAS1L and SENP3, components of the MLL1-WDR5 supercomplex involving chromatin remodeling. Our findings imply that TTLL4 could play important roles in pancreatic carcinogenesis through its polyglutamylase activity and subsequent coordination of chromatin remodeling, and might be a good molecular candidate for the development of new therapeutic strategies for pancreatic cancer.
Kashiwaya
Kotoe
K
Laboratory of Molecular Medicine, Human Genome Center, Institute of Medical Science, The University of Tokyo, Tokyo, Japan.
Nakagawa
Hidewaki
H
Hosokawa
Masayo
M
Mochizuki
Yasuo
Y
Ueda
Koji
K
Piao
Lianhua
L
Chung
Suyoun
S
Hamamoto
Ryuji
R
Eguchi
Hidetoshi
H
Ohigashi
Hiroaki
H
Ishikawa
Osamu
O
Janke
Carsten
C
Shinomura
Yasuhisa
Y
Nakamura
Yusuke
Y
D015152:Blotting, Northern; D015153:Blotting, Western; D021441:Carcinoma, Pancreatic Ductal / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation; D042002:Chromatin Assembly and Disassembly / Q000502:physiology*; D002853:Chromatography, Liquid; D056970:Co-Repressor Proteins; D005786:Gene Expression Regulation / Q000502:physiology*; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D010453:Peptide Synthases / Q000235:genetics*; D011099:Polyglutamic Acid / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D014407:Tumor Cells, Cultured
D056970:Co-Repressor Proteins; D006657:Histones; C438485:PELP1 protein, human; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; D011099:Polyglutamic Acid; D010453:Peptide Synthases; C112698:tubulin polyglutamylase