Cytokeratin19 induced by HER2/ERK binds and stabilizes HER2 on cell membranes.

Cytokeratin19 induced by HER2/ERK binds and stabilizes HER2 on cell membranes.

Cell death and differentiation (2014-10-25)

J-h Ju, S Oh, K-m Lee, W Yang, K S Nam, H-G Moon, D-Y Noh, C G Kim, G Park, J B Park, T Lee, C L Arteaga, I Shin

ABSTRACT

Cytokeratin19 (KRT19) is widely used as a biomarker for the detection of disseminated tumors. Using an LC-MS/MS proteomics approach, we found that KRT19 was upregulated in HER2-overexpressing cells and tissues. KRT19 expression was induced by HER2-downstream ERK at the transcriptional level. Another HER2-downstream kinase, Akt, was found to phosphorylate KRT19 on Ser35 and induce membrane translocation of KRT19 and remodeling of KRT19 from filamentous to granulous form. KRT19 phosphorylated by Akt could bind HER2 on the plasma membrane and stabilized HER2 via inhibition of proteasome-mediated degradation of HER2. Silencing of KRT19 by shRNA resulted in increased ubiquitination and destabilization of HER2. Moreover, treatment of KRT19 antibody resulted in downregulation of HER2 and reduced cell viability. These data provide a new rationale for targeting HER2-positive breast cancers.

MATERIALS

Product Number

Brand

Product Description

PHR1020

Supelco

Glycerin, Pharmaceutical Secondary Standard; Certified Reference Material

74255

Supelco

Sodium dodecyl sulfate, dust-free pellets, suitable for electrophoresis, Molecular Biology, ≥99.0% (GC)

436143

Sigma-Aldrich

Sodium dodecyl sulfate, ACS reagent, ≥99.0%

S6508

Sigma-Aldrich

Sodium orthovanadate, ≥90% (titration)

46401

Supelco

Cycloheximide, PESTANAL^®, analytical standard

71725

Sigma-Aldrich

Sodium dodecyl sulfate, BioUltra, Molecular Biology, ≥99.0% (GC)

71729

Sigma-Aldrich

Sodium dodecyl sulfate, ≥98.0% (GC)

43816

Sigma-Aldrich

DL-Dithiothreitol solution, BioUltra, Molecular Biology, ~1 M in H₂O

P9405

Sigma-Aldrich

O-Phospho-L-tyrosine

M5655

Sigma-Aldrich

Thiazolyl Blue Tetrazolium Bromide, powder, BioReagent, suitable for cell culture, suitable for insect cell culture, ≥97.5% (HPLC)

M1028

Sigma-Aldrich

Magnesium chloride solution, Molecular Biology, 1.00 M±0.01 M

L3771

Sigma-Aldrich

Sodium dodecyl sulfate, BioReagent, suitable for electrophoresis, Molecular Biology, ≥98.5% (GC)

L4509

Sigma-Aldrich

Sodium dodecyl sulfate, ReagentPlus^®, ≥98.5% (GC)

M8787

Sigma-Aldrich

Magnesium chloride solution, PCR Reagent, 25 mM MgCI₂solution for PCR

S3014

Sigma-Aldrich

Sodium chloride, Molecular Biology, DNase, RNase, and protease, none detected, ≥99% (titration)

S7653

Sigma-Aldrich

Sodium chloride, BioXtra, ≥99.5% (AT)

S5886

Sigma-Aldrich

Sodium chloride, BioReagent, suitable for cell culture, suitable for insect cell culture, suitable for plant cell culture, ≥99%

C7698

Sigma-Aldrich

Cycloheximide, from microbial, ≥94% (TLC)

71376

Sigma-Aldrich

Sodium chloride, BioUltra, Molecular Biology, ≥99.5% (AT)

01810

Sigma-Aldrich

Cycloheximide, ≥95% (HPLC)

71386

Sigma-Aldrich

Sodium chloride solution, BioUltra, Molecular Biology, ~5 M in H₂O

L6026

Sigma-Aldrich

Sodium dodecyl sulfate, BioXtra, ≥99.0% (GC)

M2128

Sigma-Aldrich

Thiazolyl Blue Tetrazolium Bromide, 98%

PHR1321

Supelco

Sodium chloride, Pharmaceutical Secondary Standard; Certified Reference Material

PHR1359

Supelco

Glutathione, Pharmaceutical Secondary Standard; Certified Reference Material

1295607

USP

Glycerin, United States Pharmacopeia (USP) Reference Standard

Y0000517

Glutathione, European Pharmacopoeia (EP) Reference Standard

77067

Supelco

Glycerol, analytical standard

01148

Sigma-Aldrich

Sodium fluoride, puriss., meets analytical specification of Ph. Eur., BP, USP, 98.5-100.5% (calc. to the dried substance)

201154

Sigma-Aldrich

Sodium fluoride, ACS reagent, ≥99%