Expression of smg p21A and ras p21 in epidermal neoplasms

Mori, Osamu; Hachisuka, Hiroshi; Sasai, Yoichiro; Shiku, Hiroshi

doi:10.1007/bf00372141

Cited by 3 publications

(1 citation statement)

References 11 publications

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“…These proteins are found in almost all tissues (Bokoch 1993). Like other members of the ras superfamily, rap1 has been identified in a variety of cell types, which include human epidermoid carcinoma cells, CHO cells, the Golgi of rat fibroblasts, the zymogen granule, PM and microsomal membrane of rat pancreatic acinar cells, the specific granules and PM in neutrophils, and cytosol, ␣-granules, and PM fractions of human platelets (Lapetina et al 1989;Nagata et al 1989;Matsui et al 1990;Beranger et al 1991;Maridonneau-Parini and de Gunzburg 1992;Quinn et al 1992;Schneffel et al 1992;Mori et al 1993;Berger et al 1994;Nagata et al 1995). This indicates that it serves a general function regulated via different effector pathways, depending on the cell type involved (Bokoch 1993).…”

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confidence: 99%

Immunolocalization of Rap1 in the Rat Parotid Gland: Detection on Secretory Granule Membranes

D’Silva

DiJulio

Belton

et al. 1997

J Histochem Cytochem.

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WashingtonS U M M A R Y The objective of this study was to localize rap1 in the rat parotid gland. Rap1 is a small GTP-binding protein that has been linked to phagocytosis in neutrophils and various functions in platelets. In this study, we used [ ␣-32 P]-GTP-blot overlay analysis, immunoblot analysis, and immunohistochemistry to identify rap1 in rat parotid gland. The immunohistochemical techniques included immunoperoxidase and widefield microscopy with image deconvolution. Rap1 was identified in the secretory granule membrane (SGM), plasma membrane (PM), and cytosolic (CY) fractions, with the largest signal being in the SGM fraction. The tightly bound vs loosely adherent nature of SGM-associated rap1 was determined using sodium carbonate, and its orientation on whole granules was assessed by trypsin digestion. Rap1 was found to be a tightly bound protein rather than a loosely adherent contaminant protein of the SGM. Its orientation on the cytosolic face of the secretory granule (SG) is of significance in postulating a function for rap1 because exocytosis involves the fusion of the cytoplasmic face of the SG with the cytoplasmic face of the PM, with subsequent release of granule contents (CO). Therefore, the localization and high concentration of rap1 on the SGM and its cytosolic orientation suggest that it may play a role in the regulation of secretion.

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confidence: 99%

Immunolocalization of Rap1 in the Rat Parotid Gland: Detection on Secretory Granule Membranes

D’Silva

DiJulio

Belton

et al. 1997

J Histochem Cytochem.

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Onkogene und Tumorsuppressorgene bei Hauttumoren

Weiß¹,

Herbst²

1997

Dermatologische Onkologie

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Clinicopathological and prognostic relevance of Rap1-GAP expression in melanocytic tumors

Weiß

Biwer

Schliz

et al. 1997

Archives of Dermatological Research

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Rap1-GAP protein has been identified as an inactivator of Rap1 activity, a putative endogenous antagonist of Ras proteins. The Rap1-GA1 locus maps to 1p36.1-35, the region which may harbor a gene for familial melanoma. In the present immunohistochemical study we analyzed the clinicopathological and prognostic relevance of Rap1-GAP expression in 60 benign and 103 malignant melanocytic tumors. Cytoplasmic immunoreactivity was detected in the cells of 27/60 nevi (45%) and 59/103 melanomas (57%). In the latter group the frequency of Rap1-GAP expression increased (P < 0.05) with the thickness of primary tumors and was highest in metastatic lesions. Rap1-GAP protein was detected in 15/19 subsequently recurring primary melanomas (79%) but only in 32/67 tumors (47%) of patients who remained free of disease (P < 0.05) for at least 6 years. Five out of six recurring thin melanomas (< 2 mm) were found to be immunoreactive. Although being no indicator for malignant transformation of melanocytic lesions, Rap1-GAP overexpression may represent a useful marker for identifying thin high-risk melanomas. Cytoplasmic expression of Rap1-GAP has also been observed in the cells of skin appendages and in keratinocytes, particularly in suprabasal layers of the epidermis. Therefore, Rap1-GAP is likely to be associated with cellular growth and/or differentiation. However, the present study did not provide evidence that this gene, despite its chromosomal localization, represents an early melanoma gene.

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Expression of smg p21A and ras p21 in epidermal neoplasms

Cited by 3 publications

References 11 publications

Immunolocalization of Rap1 in the Rat Parotid Gland: Detection on Secretory Granule Membranes

Immunolocalization of Rap1 in the Rat Parotid Gland: Detection on Secretory Granule Membranes

Onkogene und Tumorsuppressorgene bei Hauttumoren

Clinicopathological and prognostic relevance of Rap1-GAP expression in melanocytic tumors

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