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Kazrin, a novel periplakin-interacting protein associated with desmosomes and the keratinocyte plasma membrane.

Groot KR, Sevilla LM, Nishi K, DiColandrea T, Watt FM - J. Cell Biol. (2004)

Bottom Line: Kazrin is expressed in all layers of stratified squamous epithelia; it becomes membrane associated in the suprabasal layers, coincident with up-regulation of periplakin, and is incorporated into the cornified envelope of cultured keratinocytes.On transfection, all three kazrin isoforms have similar subcellular distributions.We conclude that kazrin is a novel component of desmosomes that associates with periplakin.

View Article: PubMed Central - PubMed

Affiliation: Keratinocyte Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3PX, UK.

ABSTRACT
Periplakin forms part of the scaffold onto which the epidermal cornified envelope is assembled. The NH2-terminal 133 amino acids mediate association with the plasma membrane and bind a novel protein, kazrin. Kazrin is highly conserved and lacks homology to any known protein. There are four alternatively spliced transcripts, encoding three proteins with different NH2 termini. Kazrin is expressed in all layers of stratified squamous epithelia; it becomes membrane associated in the suprabasal layers, coincident with up-regulation of periplakin, and is incorporated into the cornified envelope of cultured keratinocytes. Kazrin colocalizes with periplakin and desmoplakin at desmosomes and with periplakin at the interdesmosomal plasma membrane, but its subcellular distribution is independent of periplakin. On transfection, all three kazrin isoforms have similar subcellular distributions. We conclude that kazrin is a novel component of desmosomes that associates with periplakin.

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Kazrin mRNA expression. (A) RT-PCR analysis of kazrin mRNA. Forward primers specific for each of the four alternatively spliced first exons were used in combination with a reverse primer common to all splice forms. As a control for the total level of kazrin transcripts, a forward primer was used that binds within exon 2 (kazrin all) in combination with the reverse primer. Primers specific for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were used to control for input level of mRNA. (B–E) In situ hybridization of kazrin (B and C) and periplakin (D and E) using 35S-labeled antisense riboprobes in wild-type mouse skin (B and D) and tongue (C and E). Arrowheads show junction between epithelium and connective tissue. Bar, 100 μm.
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fig3: Kazrin mRNA expression. (A) RT-PCR analysis of kazrin mRNA. Forward primers specific for each of the four alternatively spliced first exons were used in combination with a reverse primer common to all splice forms. As a control for the total level of kazrin transcripts, a forward primer was used that binds within exon 2 (kazrin all) in combination with the reverse primer. Primers specific for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were used to control for input level of mRNA. (B–E) In situ hybridization of kazrin (B and C) and periplakin (D and E) using 35S-labeled antisense riboprobes in wild-type mouse skin (B and D) and tongue (C and E). Arrowheads show junction between epithelium and connective tissue. Bar, 100 μm.

Mentions: To determine if the splice variants of kazrin are differentially expressed, RT-PCR was performed on RNA isolated from primary human keratinocytes (Fig. 3 A, HK), primary dermal fibroblasts (HDF), and from three human cell lines, A431 (epidermoid carcinoma), EJ/28 (bladder carcinoma), and JAR (placental trophoblastoma). A forward primer that binds specifically within each first exon, 1a, 1b, 1c, or 1d, was used in combination with a reverse primer that binds sequences in exons 3 and 4 (Fig. 3 A). Kazrin b and d transcripts were expressed in all cell types examined. Kazrin a transcript was detectable in all cell types except A431. Kazrin c transcript was only detected in JAR cells and human dermal fibroblasts. Thus, kazrin mRNA splicing differs between cell types, and keratinocytes are predicted to express all three protein isoforms.


Kazrin, a novel periplakin-interacting protein associated with desmosomes and the keratinocyte plasma membrane.

Groot KR, Sevilla LM, Nishi K, DiColandrea T, Watt FM - J. Cell Biol. (2004)

Kazrin mRNA expression. (A) RT-PCR analysis of kazrin mRNA. Forward primers specific for each of the four alternatively spliced first exons were used in combination with a reverse primer common to all splice forms. As a control for the total level of kazrin transcripts, a forward primer was used that binds within exon 2 (kazrin all) in combination with the reverse primer. Primers specific for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were used to control for input level of mRNA. (B–E) In situ hybridization of kazrin (B and C) and periplakin (D and E) using 35S-labeled antisense riboprobes in wild-type mouse skin (B and D) and tongue (C and E). Arrowheads show junction between epithelium and connective tissue. Bar, 100 μm.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2172441&req=5

fig3: Kazrin mRNA expression. (A) RT-PCR analysis of kazrin mRNA. Forward primers specific for each of the four alternatively spliced first exons were used in combination with a reverse primer common to all splice forms. As a control for the total level of kazrin transcripts, a forward primer was used that binds within exon 2 (kazrin all) in combination with the reverse primer. Primers specific for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were used to control for input level of mRNA. (B–E) In situ hybridization of kazrin (B and C) and periplakin (D and E) using 35S-labeled antisense riboprobes in wild-type mouse skin (B and D) and tongue (C and E). Arrowheads show junction between epithelium and connective tissue. Bar, 100 μm.
Mentions: To determine if the splice variants of kazrin are differentially expressed, RT-PCR was performed on RNA isolated from primary human keratinocytes (Fig. 3 A, HK), primary dermal fibroblasts (HDF), and from three human cell lines, A431 (epidermoid carcinoma), EJ/28 (bladder carcinoma), and JAR (placental trophoblastoma). A forward primer that binds specifically within each first exon, 1a, 1b, 1c, or 1d, was used in combination with a reverse primer that binds sequences in exons 3 and 4 (Fig. 3 A). Kazrin b and d transcripts were expressed in all cell types examined. Kazrin a transcript was detectable in all cell types except A431. Kazrin c transcript was only detected in JAR cells and human dermal fibroblasts. Thus, kazrin mRNA splicing differs between cell types, and keratinocytes are predicted to express all three protein isoforms.

Bottom Line: Kazrin is expressed in all layers of stratified squamous epithelia; it becomes membrane associated in the suprabasal layers, coincident with up-regulation of periplakin, and is incorporated into the cornified envelope of cultured keratinocytes.On transfection, all three kazrin isoforms have similar subcellular distributions.We conclude that kazrin is a novel component of desmosomes that associates with periplakin.

View Article: PubMed Central - PubMed

Affiliation: Keratinocyte Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3PX, UK.

ABSTRACT
Periplakin forms part of the scaffold onto which the epidermal cornified envelope is assembled. The NH2-terminal 133 amino acids mediate association with the plasma membrane and bind a novel protein, kazrin. Kazrin is highly conserved and lacks homology to any known protein. There are four alternatively spliced transcripts, encoding three proteins with different NH2 termini. Kazrin is expressed in all layers of stratified squamous epithelia; it becomes membrane associated in the suprabasal layers, coincident with up-regulation of periplakin, and is incorporated into the cornified envelope of cultured keratinocytes. Kazrin colocalizes with periplakin and desmoplakin at desmosomes and with periplakin at the interdesmosomal plasma membrane, but its subcellular distribution is independent of periplakin. On transfection, all three kazrin isoforms have similar subcellular distributions. We conclude that kazrin is a novel component of desmosomes that associates with periplakin.

Show MeSH