spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

This Article
Right arrow Full Text (PDF)
Right arrow References
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kam, E.
Right arrow Articles by Dale, B. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kam, E.
Right arrow Articles by Dale, B. A.

Journal of Cell Science, Vol 106, Issue 1 219-226, Copyright © 1993 by Company of Biologists

JOURNAL ARTICLES

Identification of rat epidermal profilaggrin phosphatase as a member of the protein phosphatase 2A family

E Kam, KA Resing, SK Lim and BA Dale
Department of Oral Biology, University of Washington, Seattle 98195.

The aggregation of cellular intermediate filaments is an important step in the terminal differentiation of keratinocytes. It has been shown that epidermal filaggrin can cause intermediate filaments to aggregate in vitro and may also have the same function in vivo. Filaggrin is derived via dephosphorylation and proteolysis from a highly phosphorylated precursor, profilaggrin, which is found in the granular layer of the epidermis. Using casein kinase II phosphorylated filaggrin as substrate, a profilaggrin phosphatase has been partially purified from rat epidermal homogenate by three chromatographic steps (DE52, hydroxylapatite and S200 gel filtration). Profilaggrin phosphatase activity eluted from the last column has a Km of 0.12 mM and a Vmax of 8 nmol/mg/min with respect to phosphofilaggrin. Results obtained by initial rate analysis showed that the enzymatic activity is not affected by phospho-tyrosyl phosphatase inhibitors and the active fractions preferentially dephosphorylate the alpha subunit of phosphorylase kinase which has been phosphorylated by cAMP-dependent kinase. These results suggest that epidermal profilaggrin phosphatase is not a phospho-tyrosyl phosphatase or a type 1 phospho-seryl/phospho-threonyl phosphatase. Dephosphorylation is not affected by EDTA, calcium or magnesium, but is very sensitive to okadaic acid inhibition (IC50 = 80 pM), suggesting that the enzymatic activity is related to that of the protein phosphatase 2A (PP2A).(ABSTRACT TRUNCATED AT 250 WORDS)


This article has been cited by other articles:


Home page
 Mol. Biol. CellHome page
J. Reichelt, H. Bussow, C. Grund, and T. M. Magin
Formation of a Normal Epidermis Supported by Increased Stability of Keratins 5 and 14 in Keratin 10 Null Mice
Mol. Biol. Cell, June 1, 2001; 12(6): 1557 - 1568.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
K. A. Resing, C. Thulin, K. Whiting, N. Al-Alawi, and S. Mostad
Characterization of Profilaggrin Endoproteinase 1
J. Biol. Chem., November 24, 1995; 270(47): 28193 - 28198.
[Abstract] [Full Text] [PDF]


© The Company of Biologists Ltd 1993