Cloning of an Alternative Form of Plakoglobin (γ-Catenin) Lacking the Fourth Armadillo Repeat1

Abstract

Plakoglobin is a member of a protein family with a repeating amino acid motif called the armadillo repeat, and is a cytoplasmic protein found in both adherens junctions and desmosomes. Little is known about its function, but it has been shown to form distinct complexes with cadherins or desmosomal cadherins. Also, plakoglobin has been shown to form a complex with APC, a tumor suppressor gene product. We have isolated a cDNA clone encoding plakoglobin by means of the polymerase chain reaction (PCR) from a human transitional carcinoma cell line. The cDNA has the same nucleotide sequence as the previously published one [Franke et al. (1989) Proc. Natl. Acad. Sci. USA 86, 4027-4031], except that it has a deletion of 120 bp. The deleted sequence encodes the fourth armadillo repeat. Southern blot analysis of genomic DNA revealed that there is a single copy of the plakoglobin gene per haploid genome. Cloning and sequencing of a genomic DNA fragment containing the 120-bp deletion and the surrounding sequences revealed that these sequences are encoded by a single exon sequence. PCR amplification of the genomic DNA fragment of the corresponding region excluded the possible presence of the 120-bp deletion in the gene. Therefore the variant form is most likely derived through alternative splicing of precursor RNA transcripts in an exon sequence.

Functional and structural alterations of epithelial barrier properties of rat ileum following X-irradiation

“…The tight junctions, implicated in the paracellular passage of molecules, are formed by transmembrane proteins (occludin, claudin) associated with cytoplasmic proteins (ZO-1 (zona occludens 1), ZO-2, and cingulin (Cereijido et al 2000)). A similar organization was noted for adherent junctions, although protein constituents of these junctions were quite different (β-catenin as cytoplasmic protein linked to E-cadherin as membrane protein) (Ozawa et al 1994;Gumbiner 1996). The role of adherent junctions in cell-cell adhesion is complementary to that of tight junctions.…”

The prognostic value of E‐cadherin, α‐, β‐ and γ‐catenin in bladder cancer patients who underwent radical cystectomy

“…However, it is most likely identical to plakoglobin, and may function within the desmosomal plaque. 8 E-cadherin is thought to be regulated by catenins, and it has been reported in many human neoplastic tissues with the expression of a-, band g-catenin as well as E-cadherin. 9 The expression of E-cadherin, a-, band g-catenin have also been reported in TCC of the bladder.…”

Secondary structure of an armadillo single repeat from the APC protein

“…Biochemical results indicate that single amino acids in the arm region are necessa "y for the association with other proteins [10]. For armadillo ar, d plakoglobin there is genetic and biochemical evidence inplicating separate individual functions of small groups of arn repeats or even individual repeats [11,12]. Nevertheless, th.…”