Apc Expression in Normal Human Tissues

Midgley, Carol A.; White, Susan; Howitt, Rachel; Save, Vicki; Dunlop, Malcolm; Hall, Peter A.; Lane, David P.; Wyllie, Andrew H.; Bubb, Vivien J.

doi:10.1002/(sici)1096-9896(199704)181:4<426::aid-path768>3.3.co;2-k

Cited by 25 publications

(28 citation statements)

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“…In such cells, the loss of full-length APC (as shown by immunoblot with N-APC antibody, see Midgley et al (1997); the lower band is nonspecific and confirms equal loading of proteins in the samples) was accompanied by the predicted increase in cellular b-catenin levels, but there was no loss of nuclear fluorescence with M-APC antibody. We concluded that these two antibodies were not suitable for the detection of APC by IF microscopy, and such experiments (including our own, for example, figure 1 in Henderson, 2000) are unlikely to be accurate.…”

Section: Results and Discussion Detection Of Apc By If Microscopymentioning

confidence: 88%

Redefining the subcellular location and transport of APC: new insights using a panel of antibodies

2005

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Adenomatous polyposis coli (APC) is a tumour suppressor involved in colon cancer progression. We and others previously described nuclear-cytoplasmic shuttling of APC. However, there are conflicting reports concerning the localization of endogenous wild-type and tumour-associated, truncated APC. To resolve this issue, we compared APC localization using immunofluorescence (IF) microscopy and cell fractionation with nine different APC antibodies. We found that three commonly used APC antibodies showed nonspecific nuclear staining by IF and validated this conclusion in cells where APC was inactivated using small interfering RNA or Cre/Flox. Fractionation showed that wild-type and truncated APC from colon cancer cells were primarily cytoplasmic, but increased in the nucleus after leptomycin B treatment, consistent with CRM1-dependent nuclear export. In contrast to recent reports, our biochemical data indicate that APC nuclear localization is not regulated by changes in cell density, and that APC nuclear export is not prevented by truncating mutations in cancer. These results verify that the bulk of APC resides in the cytoplasm and indicate the need for caution when evaluating the nuclear accumulation of APC.

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Section: Results and Discussion Detection Of Apc By If Microscopymentioning

confidence: 88%

Redefining the subcellular location and transport of APC: new insights using a panel of antibodies

2005

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“…Furthermore, this protein tyrosine phosphatase is expressed within epithelial cells and thus shows an overlapping expression pattern with the APC protein (Hendriks et al, 1995;Midgley et al, 1997). Using the two-hybrid system we checked all ®ve PDZ domains of PTP-BL for interaction with the last 73 amino acids of the APC protein.…”

Section: Resultsmentioning

confidence: 99%

The Adenomatous Polyposis Coli-protein (APC) interacts with the protein tyrosine phosphatase PTP-BL via an alternatively spliced PDZ domain

Erdmann

Kuhlmann²,

Leßmann

et al. 2000

Oncogene

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Mutations of the tumor suppressor protein APC (Adenomatous Polyposis Coli) are linked to familiar and sporadic human colon cancer. Here we describe a novel interaction between the APC protein and the protein tyrosine phosphatase PTP-BL carrying ®ve PDZ protein ± protein interaction domains. Exclusively, the second PDZ domain (PDZ2) of PTP-BL is binding to the extreme C-terminus of the APC protein, as determined by yeast two-hybrid studies. Using surface plasmon resonance analysis we established a dissociation constant (K D ) of 8.1610 79 M. We ®nd that a naturally occurring splice insertion of ®ve amino acids (PDZ2b) abolishes its binding a nity to the APC protein. The in vivo interaction between PTP-BL and the APC protein was shown by coprecipitation experiments in transfected COS cells. Furthermore, in cultured epithelial Madine Carnine Kidney cells the subcellular colocalization was demonstrated for the nucleus and also for the tips of cellular extensions. The interaction of the APC protein with a protein tyrosine phosphatase may indirectly modulate the steady state levels of tyrosine phosphorylations of associated proteins, such as b-catenin playing a major role in the regulation of cell division, migration and cell adhesion. Oncogene (2000) 19, 3894 ± 3901.

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“…Silencing of Apc + expression. Antibody 3122 to Apc (Midgley et al 1997) was used for the detection of wild-type Apc antigen by immunoperoxidase (A. R. Shoemaker and C. Midgley, unpublished data). Normal crypts display abundant antigen, but adenomatous tissue is negative in tumours that form in AKRÁMin animals after neonatal exposure to ENU.…”

Section: The Polyclonal Structure Of Early Adenomas In Min Micementioning

confidence: 99%

The intestinal epithelium and its neoplasms: genetic, cellular and tissue interactions

Dove

Cormier

Gould

et al. 1998

Phil. Trans. R. Soc. Lond. B

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The Min (multiple intestinal neoplasia) strain of the laboratory mouse and its derivatives permit the fundamental study of factors that regulate the transition between normal and neoplastic growth. A gene of central importance in mediating these alternative patterns of growth is Apc, the mouse homologue of the human adenomatous polyposis coli (APC) gene. When adenomas form in the Min mouse, both copies of the Apc gene must be inactivated. One copy is mutated by the nonsense Apc allele carried in heterozygous form in this strain. The other copy can be silenced by any of several mechanisms. These range from loss of the homologue bearing the wild-type Apc allele; to interstitial deletions surrounding the wild-type allele; to intragenic mutation, including nonsense alleles; and ¢nally, to a reduction in expression of the locus, perhaps owing to mutation in a regulatory locus. Each of these proposed mechanisms may constitute a two-hit genetic process as initially posited by Knudson; however, apparently the two hits could involve either a single locus or two loci. The kinetic order for the transition to adenoma may be still higher than two, if polyclonal adenomas require stronger interactions than passive fusion.The severity of the intestinal neoplastic phenotype of the Min mouse is strongly dependent upon loci other than Apc. One of these, Mom1, has now been rigorously identi¢ed at the molecular level as encoding an active resistance conferred by a secretory phospholipase. Mom1 acts locally within a crypt lineage, not systemically. Within the crypt lineage, however, its action seems to be non-autonomous: when tumours arise in Mom1 heterozygotes, the active resistance allele is maintained in the tumour (MOH or maintenance of heterozygosity). Indeed, the secretory phospholipase is synthesized by post-mitotic Paneth cells, not by the proliferative cells that presumably generate the tumour. An analysis of autonomy of modi¢er gene action in chimeric mice deserves detailed attention both to the number of genetic factors for which an animal is chimeric and to the clonal structure of the tissue in question.Beyond Mom1, other loci can strongly modify the severity of the Min phenotype. An emergent challenge is to ¢nd ways to identify the full set of genes that interact with the intestinal cancer predisposition of the Min mouse strain. With such a set, one can then work, using contemporary mouse genetics, to identify the molecular, cellular and organismal strategies that integrate their functions. Finally, with appropriately phenotyped human families, one can investigate by a candidate approach which modifying factors in£uence the epidemiology of human colon cancer. Even if a candidate modi¢er does not explain any of the genetic epidemiology of colon cancer in human populations, modi¢er activities discovered by mouse genetics provide candidates for chemopreventive and/or therapeutic modalities in the human.

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Apc Expression in Normal Human Tissues

Cited by 25 publications

References 0 publications

Redefining the subcellular location and transport of APC: new insights using a panel of antibodies

Redefining the subcellular location and transport of APC: new insights using a panel of antibodies

The Adenomatous Polyposis Coli-protein (APC) interacts with the protein tyrosine phosphatase PTP-BL via an alternatively spliced PDZ domain

The intestinal epithelium and its neoplasms: genetic, cellular and tissue interactions

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