scholarly journals Immunochemical evidence for a unique GPI-anchored carbonic anhydrase isozyme in human cardiomyocytes

2000 ◽  
Vol 278 (4) ◽  
pp. H1335-H1344 ◽  
Author(s):  
Anja Sylvia Knüppel-Ruppert ◽  
Gerolf Gros ◽  
Wolfgang Harringer ◽  
Hans-Peter Kubis
Keyword(s):  
Carbonic Anhydrase ◽  
Microsomal Fraction ◽  
Cell Types ◽  
Human Cardiomyocytes ◽  
Ca Ix ◽  
Specific Distribution ◽  
Carbonic Anhydrase Isozyme ◽  
Membrane Bound ◽  
Membrane Anchoring ◽  
Triton X

To clarify the controversial question of cell-specific distribution of carbonic anhydrase (CA) in the heart, endothelial cells and cardiomyocytes were isolated from porcine and human hearts and were characterized with cell-specific markers. CA activity was found in the microsomal fraction of both cell types. It was shown by Triton X-114 phase separation that both cell types possess a membrane-bound form of CA. These CAs share the same mechanism of membrane-anchoring via glycosylphosphatidylinositol (GPI), which excludes identity with transmembrane isoforms CA IX or CA XII. Western blotting analysis of human microsomes with anti-human CA IV antibodies revealed a marked difference in immunoreactivity. Endothelial CA activity resulted in 11-fold stronger CA IV bands compared with identical amounts of myocytic CA activity, indicating that cardiac endothelium and cardiomyocytes possess immunologically distinct forms of CA. We conclude that in human hearts CA IV is associated with the endothelium, whereas most of the CA in myocytes is not identical with one of the known CA isozymes. This suggests that cardiomyocytic CA is a novel isozyme.

Expression of membrane-associated carbonic anhydrase isoforms IV, IX, XII, and XIV in the rabbit: induction of CA IV and IX during maturation

2005 ◽  
Vol 288 (5) ◽  
pp. R1256-R1263 ◽  
Author(s):  
Jeffrey M. Purkerson ◽  
George J. Schwartz
Keyword(s):  
Skeletal Muscle ◽  
Carbonic Anhydrase ◽  
Gall Bladder ◽  
Plasma Membranes ◽  
Rabbit Kidney ◽  
Α Subunit ◽  
Anion Transporters ◽  
Ca Ix ◽  
Membrane Bound ◽  
Physiological Demands

Several carbonic anhydrase (CA) isoforms are associated with plasma membranes. It is probable that these enzymes interact with anion transporters to facilitate the movement of HCO3− into or out of the cell. A better knowledge of CA isoform expression in a given tissue would facilitate a systematic examination of any associations with such transporters. We examined the expression of CAs IV, IX, XII, and XIV mRNAs in rabbit tissues, including kidney, heart, lung, skeletal muscle, liver, pancreas, gall bladder, stomach, small intestine, colon, and spleen, using quantitative real-time reverse transcription polymerase chain reaction (RT-PCR). CA IV mRNA was mainly in kidney, heart, lung, colon, and gall bladder. CA IX mRNA was restricted to stomach, gall bladder, duodenum, and early jejunum. CA XII mRNA was found in kidney and colon. CA XIV mRNA was localized to heart, lung, skeletal muscle, and liver. The data indicate that there are different patterns of CA expression in various tissues: CA IX was expressed in the proximal gastrointestinal tract, whereas CA XII and CA IV were more distal. CA IV and CA XII are important kidney isoforms. CA XIV was abundant in metabolically active tissues such as liver, heart, lung, and skeletal muscle. Some significant species differences were noted in the expression of some of these isoforms; for example, CA XIV is not expressed in rabbit kidney, despite being abundant in mouse kidney. Maturational studies showed that the expression of CA IX mRNA and protein increased markedly with weaning (∼3–4 postnatal wk) and was well correlated with the maturational expression of the α-subunit of the gastric H+,K+-ATPase, suggesting that function of CA IX and the gastric H+ pump might be linked in the digestion of adult foodstuffs. The unique pattern of membrane-bound CA isoforms suggests different functional associations with transporters, depending on the physiological demands on the tissue.

scholarly journals Structure of the carbonic anhydrase VI (CA6) gene: evidence for two distinct groups within the α-CA gene family

1999 ◽  
Vol 344 (2) ◽  
pp. 385-390 ◽  
Author(s):  
Weiping JIANG ◽  
Dwijendra GUPTA
Keyword(s):  
Carbonic Anhydrase ◽  
Untranslated Region ◽  
Sequence Similarity ◽  
Ca Ix ◽  
Its Gene ◽  
Exon 1 ◽  
Membrane Bound ◽  
Mature Enzyme ◽  
Gene Structures ◽  
Carbonic Anhydrase Vi

The secreted carbonic anhydrase (CA VI) is believed to be one of the oldest mammalian CAs in evolutionary terms. To elucidate its gene structure and compare it with other members of the α-CA family, we cloned genomic fragments encoding the bovine CA6 gene and determined its exon/intron organization. The gene spans approx. 25 kb and consists of eight exons and seven introns. Exon 1 encodes the 5′ untranslated region, the signal peptide and the N-terminus of the mature enzyme. Exon 8 encodes the 3′ untranslated region and the C-terminal extension that is unique to CA VI. Exons 2-7 encode the CA domain, which shows significant sequence similarity to other CAs. Two distinct groups exist in the α-CA family on the basis of a comparison of the known gene structures. One group consists of the cytoplasmic (CA I, II, III and VII) and mitochondrial (CA V) members. The other group consists of the membrane-bound (CA IV and IX) and secreted (CA VI) members. In particular, the seven exon/intron boundaries in the CA domain of the CA6 gene are conserved in the CA9 gene, which encodes the multidomain protein CA IX that is overexpressed in tumours and has transforming potential.

scholarly journals Carbonic anhydrase in skeletal and cardiac muscle from rabbit and rat

1992 ◽  
Vol 282 (1) ◽  
pp. 165-171 ◽  
Author(s):  
C Geers ◽  
D Krüger ◽  
W Siffert ◽  
A Schmid ◽  
W Bruns ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Cardiac Muscle ◽  
High Activity ◽  
Skeletal Muscles ◽  
Carbonic Anhydrases ◽  
Striated Muscles ◽  
Membrane Bound ◽  
Triton X ◽  
Dextran Solution ◽  
Low Activity

We have studied the distribution of carbonic anhydrases (CA) in several skeletal muscles of the hindlimb of rabbits and rats and in cardiac muscle of the rabbit. To remove erythrocyte CA, hindlimbs and hearts were thoroughly perfused with dextran solution, and the effectiveness of the perfusion was in most cases assessed by determining the contamination of the muscles with radioisotopes that had been used to label the erythrocytes before the perfusion was started. We observed three forms of CA: (1) cytosolic (sulphonamide-resistant) CA III; (2) a cytosolic sulphonamide-sensitive CA, probably isoenzyme II; (3) a membrane-bound form that was extracted from the particulate fraction using Triton X-100. These CA isoforms were distributed as follows. (1) CA III is located in the cytoplasm of slow, oxidative skeletal muscles and is absent from or low in fast skeletal and cardiac muscle; this holds for rabbits and rats and is identical with the pattern previously described for several other species. (2) The cytosolic sulphonamide-sensitive CA is present in fast rabbit muscles and absent from slow muscles of this species. In contrast, all skeletal muscles of the rat studied here lack, or possess only very low, activity of this isoenzyme. (3) The membrane-bound form of CA is present in all rabbit muscles studied; its activity appears somewhat higher in fast than in slow skeletal muscles. (4) Cardiac muscle constitutes an exception among all striated muscles of the rabbit as it possesses no form of cytosolic CA but a high activity of the membrane-bound form.

Membrane-bound carbonic anhydrase in the heart

1992 ◽  
Vol 262 (2) ◽  
pp. H577-H584 ◽  
Author(s):  
W. Bruns ◽  
G. Gros
Keyword(s):  
Carbonic Anhydrase ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Integral Membrane Protein ◽  
Rabbit Heart ◽  
Microsomal Membranes ◽  
Membrane Bound ◽  
The One ◽  
Triton X

Microsomal membranes from bovine heart homogenates were subfractionated by density gradient centrifugation. Fractions with high levels of a sarcolemmal (SL) marker are enriched in specific carbonic anhydrase (CA) activity up to ninefold compared with the microsomes. Fractions with high levels of a sarcoplasmic reticulum marker and a mitochondrial marker, respectively, exhibit specific CA activities that are similar to the one found in the microsomes. Determination of cytosolic markers reveals that the CA activity in the SL fraction is not due to contamination by cytosolic CA, and it is shown by Triton X-114 phase separation that the CA activity is due to an integral membrane protein. In cryosections from rabbit heart the SL region of cardiomyocytes is stained by the fluorescent CA inhibitor dansylsulfonamide. Intracellular staining occurs also, with a pattern suggesting the presence of CA associated with intracellular membranes. Although it cannot be excluded that there is a contribution by endothelial membranes, it appears likely that most CA of the heart is bound to the SL. The possible involvement of the enzyme in extracellular proton buffering is discussed.

Expression of hypoxia-inducible, membrane-bound carbonic anhydrase isozyme XII in mouse tissues

2004 ◽  
Vol 277A (1) ◽  
pp. 171-177 ◽  
Author(s):  
Piia Halmi ◽  
Jonna Lehtonen ◽  
Abdul Waheed ◽  
William S. Sly ◽  
Seppo Parkkila
Keyword(s):  
Carbonic Anhydrase ◽  
Mouse Tissues ◽  
Carbonic Anhydrase Isozyme ◽  
Membrane Bound

scholarly journals Evidence for membrane-bound carbonic anhydrase in the air bladder of bowfin (Amia calva), a primitive air-breathing fish.

1998 ◽  
Vol 201 (14) ◽  
pp. 2205-2212 ◽  
Author(s):  
M R Gervais ◽  
B L Tufts
Keyword(s):  
Carbonic Anhydrase ◽  
Microsomal Fraction ◽  
Carbonic Anhydrase Activity ◽  
Carbonic Anhydrase Inhibitor ◽  
Cytoplasmic Fraction ◽  
Air Breathing ◽  
Membrane Attachment ◽  
Membrane Bound ◽  
Amia Calva ◽  
Microsomal Pellet

The purpose of this study was to examine the subcellular distribution and isoenzyme characteristics of carbonic anhydrase from the gills and respiratory air bladder of bowfin Amia calva, a primitive air-breathing fish. Separation of subcellular fractions by differential centrifugation revealed that the vast majority of carbonic anhydrase from the gills of bowfin originated from the cytoplasmic fraction. Washing of the gill microsomal pellet also indicated that the carbonic anhydrase originally associated with this pellet was largely due to contamination from the cytoplasmic fraction. Experiments with a carbonic anhydrase inhibitor, sulphanilamide, and the plasma carbonic anhydrase inhibitor from this species confirmed that the bowfin gill probably contains only one carbonic anhydrase isoenzyme which had properties resembling those of CA II. In contrast to the situation in the gills, a relatively large percentage (27%) of the total air bladder carbonic anhydrase was associated with the microsomal fraction. Washing of the air bladder microsomal pellet removed little of the carbonic anhydrase activity, indicating that most of the carbonic anhydrase in the microsomal fraction was associated with the membranes. Like the mammalian pulmonary CA IV isoenzyme, microsomal carbonic anhydrase from the bowfin air bladder was less sensitive to the bowfin plasma carbonic anhydrase inhibitor, sodium dodecylsulphate (SDS) and sulphanilamide than was cytoplasmic carbonic anhydrase from the air bladder. Microsomal carbonic anhydrase from the bowfin air bladder also resembled CA IV in that it appears to be anchored to the membrane via a phosphatidylinositol-glycan linkage which could be cleaved by phosphatidylinositol-specific phospholipase C. Taken together, these results suggest that a membrane-bound carbonic anhydrase isoenzyme resembling mammalian CA IV in terms of inhibition characteristics and membrane attachment is present in the air-breathing organ of one of the most primitive air-breathing vertebrates.

scholarly journals Triton Hodge Test: Improved Protocol for Modified Hodge Test for Enhanced Detection of NDM and Other Carbapenemase Producers

2015 ◽  
Vol 54 (3) ◽  
pp. 640-649 ◽  
Author(s):  
Fernando Pasteran ◽  
Lisandro J. Gonzalez ◽  
Ezequiel Albornoz ◽  
Guillermo Bahr ◽  
Alejandro J. Vila ◽  
...  
Keyword(s):  
Clinical Isolates ◽  
New Delhi ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Test Specificity ◽  
Membrane Bound ◽  
Membrane Anchoring ◽  
Triton X ◽  
Encoding Genes ◽  
Large Improvement

Accurate detection of carbapenemase-producing Gram-negative bacilli is of utmost importance for the control of nosocomial spread and the initiation of appropriate antimicrobial therapy. The modified Hodge test (MHT), a carbapenem inactivation assay, has shown poor sensitivity in detecting the worldwide spread of New Delhi metallo-β-lactamase (NDM). Recent studies demonstrated that NDM is a lipoprotein anchored to the outer membrane in Gram-negative bacteria, unlike all other known carbapenemases. Here we report that membrane anchoring of β-lactamases precludes detection of carbapenemase activity by the MHT. We also show that this limitation can be overcome by the addition of Triton X-100 during the test, which allows detection of NDM. We propose an improved version of the assay, called the Triton Hodge test (THT), which allows detection of membrane-bound carbapenemases with the addition of this nonionic surfactant. This test was challenged with a panel of 185 clinical isolates (145 carrying known carbapenemase-encoding genes and 40 carbapenemase nonproducers). The THT displayed test sensitivity of >90% against NDM-producing clinical isolates, while improving performance against other carbapenemases. Ertapenem provided the highest sensitivity (97 to 100%, depending on the type of carbapenemase), followed by meropenem (92.5 to 100%). Test specificity was not affected by the addition of Triton (87.5% and 92.5% with ertapenem and meropenem, respectively). This simple inexpensive test confers a large improvement to the sensitivity of the MHT for the detection of NDM and other carbapenemases.

scholarly journals Distinct Expression Patterns of Carbonic Anhydrase IX in Clear Cell, Microcystic, and Angiomatous Meningiomas

2019 ◽  
Vol 78 (12) ◽  
pp. 1081-1088
Author(s):  
Rati Chkheidze ◽  
Patrick J Cimino ◽  
Kimmo J Hatanpaa ◽  
Charles L White ◽  
Manuel Ferreira ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Clear Cell ◽  
Expression Patterns ◽  
Carbonic Anhydrase Ix ◽  
World Health ◽  
Loss Of Function ◽  
Ca Ix ◽  
Hypoxia Marker ◽  
Other World ◽  
Health Organization

Abstract Clear cell, microcytic, and angiomatous meningiomas are 3 vasculature-rich variants with overlapping morphological features but different prognostic and treatment implications. Distinction between them is not always straightforward. We compared the expression patterns of the hypoxia marker carbonic anhydrase IX (CA-IX) in meningiomas with predominant clear cell (n = 15), microcystic (n = 9), or angiomatous (n = 11) morphologies, as well as 117 cases of other World Health Organization recognized histological meningioma variants. Immunostaining for SMARCE1 protein, whose loss-of-function has been associated with clear cell meningiomas, was performed on all clear cell meningiomas, and selected variants of meningiomas as controls. All clear cell meningiomas showed absence of CA-IX expression and loss of nuclear SMARCE1 expression. All microcystic and angiomatous meningiomas showed diffuse CA-IX immunoreactivity and retained nuclear SMARCE1 expression. In other meningioma variants, CA-IX was expressed in a hypoxia-restricted pattern and was highly associated with atypical features such as necrosis, small cell change, and focal clear cell change. In conclusion, CA-IX may serve as a useful diagnostic marker in differentiating clear cell, microcystic, and angiomatous meningiomas.

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