Type II keratins are phosphorylated on a unique motif during stress and mitosis in tissues and cultured cells

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)


Interna författare/redaktörer


Publikationens författare: Toivola DM, Zhou Q, English LS, Omary MB
Förläggare: AMER SOC CELL BIOLOGY
Publiceringsår: 2002
Tidskrift: Molecular biology of the cell
Tidskriftsakronym: MOL BIOL CELL
Volym: 13
Nummer: 6
Artikelns första sida, sidnummer: 1857
Artikelns sista sida, sidnummer: 1870
Antal sidor: 14
ISSN: 1059-1524


Abstrakt

Epithelial cell keratins make up the type I (K9-K20) and type II (K1-K8) intermediate filament proteins. In glandular epithelia, K8 becomes phosphorylated on S73 ((71)LLpSPL) in human cultured cells and tissues during stress, apoptosis, and mitosis. Of all known proteins, the context of the K8 S73 motif (LLS/TPL) is unique to type II keratins and is conserved in epidermal K5/K6, esophageal K4, and type II hair keratins, except that serine is replaced by threonine. Because knowledge regarding epidermal and esophageal keratin regulation is limited, we tested whether K4-K6 are phosphorylated on the LLTPL motif. K5 and K6 become phosphorylated in vitro on threonine by the stress-activated kinase p38. Site-specific anti-phosphokeratin antibodies to LLpTPL were generated, which demonstrated negligible basal K4-K6 phosphorylation. In contrast, treatment of primary keratinocytes and other cultured cells, and ex vivo skin and esophagus cultures, with serine/threonine phosphatase inhibitors causes a dramatic increase in K4-K6 LLpTPL phosphorylation. This phosphorylation is accompanied by keratin solubilization, filament reorcanization, and collapse. K5/K6 LLTPL phosphorylation occurs in vivo during mitosis and apoptosis induced by UV light or anisomycin, and in human psoriatic skin and squamous cell carcinoma. In conclusion, type II keratins of proliferating epithelia undergo phosphorylation at a unique and conserved motif as part of physiological mitotic and stress-related signals.

Senast uppdaterad 2019-06-12 vid 04:48