Proteomic analyses of intermediate filaments reveals cytokeratin8 is highly acetylated--implications for colorectal epithelial homeostasis.
Butyrate is a critical cancer-preventive element in the colon milieu whose mechanism of action is unclear, but appears to be mediated through inhibition of histone deacetylases (HDACs) and consequent alterations in global protein acetylation. Cytokeratins (CKs) have roles in cytoskeletal function as components of the intermediate filaments (IFs) and this involves CKs in the regulation of tissue homeostasis of high-turnover epithelia such as the colon. We used a 2-D gel/MS analysis to characterise the proteome of IFs, and a novel monitoring-initiated detection and sequencing (MIDAS) approach to identify acetylation sites on principal proteins. We report that CKs are highly acetylated in a colon cancer cell line, with five acetylation sites characterised on CK8 and a further one on CK18. Acetylation of CK8 is responsive to butyrate. HDAC5 is the deacetylase associated with IFs. These data indicate a novel action of butyrate as a cancer preventive agent. Acetylation of CK8 may be associated with IFs stabilisation and thereby provide a candidate mechanism for the appropriate retention or loss of epithelial cells from the flat mucosa.
Leech
Siân H
SH
Human Nutrition Unit, Division of Clinical Sciences North, University of Sheffield, Royal Hallamshire Hospital, Sheffield, UK.
Evans
Caroline A
CA
Shaw
Leila
L
Wong
Chi H
CH
Connolly
Joanne
J
Griffiths
John R
JR
Whetton
Anthony D
AD
Corfe
Bernard M
BM
D000107:Acetylation; D000595:Amino Acid Sequence; D002087:Butyrates / Q000494:pharmacology*; D015179:Colorectal Neoplasms / Q000209:etiology; D045325:HCT116 Cells; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D007382:Intermediate Filaments / Q000737:chemistry*; D007413:Intestinal Mucosa / Q000187:drug effects*; D053538:Keratin-18 / Q000378:metabolism; D053533:Keratin-8 / Q000378:metabolism*; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000378:metabolism
D002087:Butyrates; D053538:Keratin-18; D053533:Keratin-8; D020033:Protein Isoforms