Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.3.14 (ATP synthase)
 7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intracellular acidic compartments serve several functions, including uptake of nutrients, processing and sorting of secreted and membrane-bound proteins, and even entry of viruses into cells. In this study, we examined the distribution of acidic compartments in normal human keratinocytes cultured in serum-free medium. Acridine orange was used to stain acidic organelles (red fluorescence), and adherent cells were evaluated by fluorescence microscopy and by interactive laser cytometry (ILC). Keratinocytes cultured in low [Ca++] (0.15 mM) exhibited morphologic characteristics associated with basal cells; red acidic vesicles in these cells were aggregated around the nucleus, sparing the peripheral cytoplasm. After 24 h of culture in high [Ca++] (1.5 mM) keratinocytes showed morphologic changes associated with differentiated cells, including increased number and dispersal of red vesicles to the periphery of the cytoplasm. Keratinocytes cultured in 0.15 mM [Ca++], but treated with phorbol 12-myristate 13-acetate (PMA, 5-100 ng/ml) to induce terminal differentiation, developed similar features. Incubation in media with either high [Ca++] or PMA also induced radial extension of the microtubule network, suggesting that the distribution of acidic organelles occurs along this network. Finally, crude keratinocyte membranes were evaluated by radioactive assay for the presence of three ion-translocating ATPase activities, plasma membrane Na/K ATPase, mitochondrial ATPase, and vacuolar H+ pump ATPase, the latter being the activity responsible for acidification of intracellular compartments. Both basaloid and differentiated keratinocytes exhibited similar vacuolar H+ pump ATPase activity, as measured by its sensitivity to bafilomycin.
J Invest Dermatol 1992 Jun
PMID:Increased number and microtubule-associated dispersal of acidic intracellular compartments accompany differentiation of cultured human keratinocytes. 153 43

With the exception of two cases, keratin is not expressed in cultured human melanoma cells. Using 2D-PAGE, immunological and electron microscopic analyses, we found keratin subunits in five established cultured cell lines derived from primary, recurrent and metastasized melanomas. The keratin subunits were composed of K1, K5, K10, K14, K15 and K18 in all cell lines examined, together with vimentin. In addition, K8, K16 and K18 expression were demonstrated in recurrent and metastasized cell lines. The results of the present and our previous study [Katagata Y, et al. J Dermatol Sci 1996;13:219-227] indicate that expression of keratin in melanoma cells may be a universal phenomenon. A specific increase in the proportion of K5 among the keratin subunits was suggestive of the nature of melanoma cells. Moreover, we detected two polypeptides that migrated on 2D-PAGE at positions which did not correspond to those of any keratin subunit. The amino acid sequences of these two polypeptides were determined; one was the human ATP synthase alpha-chain but the other did not match any known polypeptide in our homology search.
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PMID:Keratin expression and its significance in five cultured melanoma cell lines derived from primary, recurrent and metastasized melanomas. 914 75

Differences in treatment solution affect the efficiency of keratin extraction in cultured human squamous cell carcinomas, malignant melanomas, and melanocytes. Using an aqueous solution that is excellent for cultured cells, we focused this study on the expression of keratin subunits in the spontaneously immortalized human keratinocyte cell line HaCaT. We extracted several keratin (K) subunits, namely K4, K7, K8, K15, K17, and K18, and ATP synthase alpha-chain, in addition to those previously reported by Boukamp et al. (J Cell Biol 1988;106:761-771) in human HaCaT keratinocytes. In particular, K8 and K18 subunits, which are related to tumorigenesis, may be very important subunits within the specificities of immortalized HaCaT cells. Vimentin, which is frequently co-expressed in cultured epithelial cell lines, was not expressed.
J Dermatol Sci 1999 Feb
PMID:Detecting expression of keratins 8/18 in human HaCaT keratinocytes. 1009 6

The synthesis of keratin is considered to occur in epithelial and epidermal cells. Previous studies have not reported on keratin synthesis within melanocytes that derive from neural crest cells. Epithelial and neural crest cells originally develop from ectodermal tissue. We previously reported that the expression of keratin is a universal phenomenon seen in cultured melanoma cell lines, as demonstrated by two-dimensional polyacrylamide gel electrophoresis, western blot, and electron microscopy analyses. To further investigate the specificity of keratin function in melanocytic cells, we first examined the presence of keratin proteins in cultured human melanocytes, and unexpectedly found keratin subunits in melanocytes by the above-mentioned procedures. The keratin (K) subunits were composed of K1, K5, K8, K10, K14, K16, and K18, together with vimentin. Neural crest cells, which contain immature embryonic melanocytes developing from ectoderm, already expressed keratins; however, under electron microscopy, the expressed keratin did not form filamentous structures. Although the ATP synthase alpha-chain, which is expressed universally in cultured epidermal tumor cell lines, was also expressed in cultured melanocytes and neural crest cells, a novel malignant melanoma-related protein (MMRP) was absent in melanocytes and neural crest cells. We concluded that keratin subunits are present in both cells, but do not construct keratin filaments.
J Investig Dermatol Symp Proc 1999 Sep
PMID:Keratin subunit expression in human cultured melanocytes and mouse neural crest cells without formation of filamentous structures. 1053 84

Carboxyfullerenes (CF) act as free radical scavengers in many cell settings and prevent apoptosis in vitro and in vivo. CF protect normal human keratinocytes from UVB-induced apoptosis, although the mechanisms underlying this effect remain to be clarified. Double-staining confocal laser microscopy revealed that CF penetrate the cell and colocalize with cytokeratin-18 within cytoplasm. This localization was confirmed by transmission electron microscopy that showed CF intermingled with keratin filaments. Moreover, double-staining with the mitochondrial marker anti-F1-ATPase antibody demonstrated that CF are expressed in mitochondria. Transmission electron microscopy confirmed that CF actually localize within mitochondria. Then, normal human keratinocytes were UVB-irradiated in the presence or absence of CF at different doses. CF protected keratinocytes from apoptosis induced by reactive oxygen species. CF scavenging effect is associated with a partial blockade of the UVB-induced intrinsic apoptotic pathway by down-modulating caspase-9 activation and cytochrome c release, and by inhibiting the down-regulation of the inhibitor of apoptosis proteins (IAP) survivin, livin, IAP-1 and IAP-2. Finally, CF prevented the cleavage of Bid, up-regulation of Bad and down-regulation of Mcl-1 induced by UVB. Taken together, these results indicate that CF penetrate human keratinocytes, localize within mitochondria where they act both by scavenging free radicals and by protecting cells from apoptosis.
Exp Dermatol 2007 May
PMID:Carboxyfullerenes localize within mitochondria and prevent the UVB-induced intrinsic apoptotic pathway. 1743 86