Identification of two distinct protein carboxyl methyltransferases in eucaryotic cells

Solomon, R.; Katzir, Orit; Egozi, Yaakov; Kloog, Yoel

doi:10.1016/0014-5793(88)81045-7

Cited by 5 publications

(3 citation statements)

References 13 publications

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“…The molecular mass calculated from the amino acid sequences is 24.5 kDa, in good agreement with the apparent molecular sizes of purified PCMTs determined by SDS/PAGE, which are in the 25-27 kDa range [31]. However, larger sizes of 30 and 34 kDa have also been reported for the enzyme from Torpedo ocellata electric organ [32] and Xenopus laevis oocytes [33] respectively.…”

Section: Introductionsupporting

confidence: 76%

Immunochemical characterization of l-isoaspartyl-protein carboxyl methyltransferase from mammalian tissues

Boivin

Bilodeau

Béliveau

1995

Biochemical Journal

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Polyclonal antibodies were raised against a synthetic peptide corresponding to a sequence of 14 amino acid residues found near the C-terminus of L-isoaspartyl (D-aspartyl)-protein carboxyl methyltransferase (PCMT). The affinity-purified antibodies were used to detect the methyltransferase by Western-blot analysis in cytosolic and membrane fractions from several mammalian tissues. A protein of 27 kDa was detected in the cytosol of most tissues; co-incubation with the peptide used for immunization abolished the detection. The identity of the 27 kDa protein as a PCMT was demonstrated by renaturation of PCMT activity from SDS/polyacrylamide gels. The methyltransferase from brain cytosol was immunoprecipitated by the anti-PCMT antibodies and Protein A-agarose, indicating that the native protein was recognized by the antibodies. PCMT was also immunodetected in crude membranes from brain, testes and heart, and in purified membranes from kidney cortex. The expression of the methyltransferase was higher in bovine and human brain than in rat tissues. The bovine enzyme had a greater electrophoretic mobility, suggesting small structural differences. The membrane-bound methyltransferase could be extracted with detergents above their critical micellar concentration, but not with salt, alkaline or urea solutions suggesting that the binding of the enzyme to membranes is hydrophobic by nature. Anti-PCMT antibodies provide an interesting tool for studies regarding the expression of these enzymes in both soluble and membrane fractions of various cell types.

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Section: Introductionsupporting

confidence: 76%

Immunochemical characterization of l-isoaspartyl-protein carboxyl methyltransferase from mammalian tissues

Boivin

Bilodeau

Béliveau

1995

Biochemical Journal

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“…The SARS-CoV-2 epidemic has resulted in 334 981 confirmed cases with 14 652 deaths reported (as of 24 March 2020). SARS-CoV-2 was identified as a highly infectious novel coronavirus [1], which is highly infectious in adults and older adults. A recent report indicated a lower incidence rate of SARS-CoV-2 infection in patients with chronic lung diseases [2]; however, patients with a chronic lung disease could have severe outcomes once they are infected.…”

Section: Introductionmentioning

confidence: 99%

Alteration in angiotensin-converting enzyme 2 by PM₁during the development of emphysema in rats

et al. 2020

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IntroductionAngiotensin-converting enzyme 2 (ACE2) provides an adhesion site for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Patients with COPD could have severe outcomes after SARS-CoV-2 infection. The objective of this study was to investigate ACE2 regulation by air pollution during the development of COPD.MethodsSprague Dawley rats were exposed to unconcentrated traffic-related air pollution for 3 and 6 months. We examined lung injury markers, oxidative stress, inflammation, emphysema, ACE2 and angiotensin II receptor type 1 (AT1) and 2 (AT2) in the lungs after exposure.ResultsLung injury occurred due to an increase in permeability and lactate dehydrogenase cytotoxicity was observed after 6 months of exposure to fine particulate matter of <1 μm in aerodynamic diameter (PM1). An α1-antitrypsin deficiency and neutrophil elastase production with emphysema development were observed after 6 months of PM1 exposure. 8-isoprostane and interleukin-6 were increased after 3 and 6 months of PM1 exposure. Caspase-3 was increased after exposure to PM1 for 6 months. Upregulation of ACE2 was found after 3 months of PM1 exposure; however, ACE2 had decreased by 6 months of PM1 exposure. AT1 and AT2 had significantly decreased after exposure to PM1 for 6 months. Furthermore, smooth muscle hypertrophy had occurred after 6 months of PM1 exposure.ConclusionsIn conclusion, short-term exposure to PM1 increased the ACE2 overexpression in lungs. Long-term exposure to PM1 decreased the ACE2 overexpression in emphysema. Air pollution may be a risk for SARS-CoV-2 adhesion during the development of COPD.

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“…It is noteworthy that, although the molecular mass of L-isoaspartyl PCMTs is generally close to 27 kDa (Clarke, 1985), previous reports have documented the existence of distinct forms of PCMT with different molecular masses. In Torpedo ocellanata, two distinct PCMTs of 27 and 35 kDa have been described (Solomon et al, 1988), and two forms of PCMT, with distinct subcellular localization, have been identified in Xenopus laevis oocytes (27 and 34 kDa) (O'Connor, 1987).…”

Section: Discussionmentioning

confidence: 99%

Asymmetrical distribution of l-isoaspartyl protein carboxyl methyltransferases in the plasma membranes of rat kidney cortex

Gingras

Boivin

Béliveau

1994

Biochemical Journal

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We have studied the distribution of membrane-associated L-isoaspartyl protein carboxyl methyltransferases (PCMTs) in plasma membranes purified from rat kidney cortex. Addition of CHAPS to brush-border membranes (BBM) and basolateral membranes (BLM) was required to measure optimal membrane-dependent methylation of ovalbumin and TS-isoD-YSKY, substrates of L-isoaspartyl PCMTs. Extraction of both membrane-associated enzymes was achieved with detergents, but not with high-salt solutions, suggesting a strong membrane attachment. However, upon phase partitioning using Triton X-114, both enzymes were predominantly associated with the detergent-poor phase, suggesting a relatively hydrophilic nature. The enzymes showed similar catalytic properties such as substrate recognition and affinity towards the methyl donor, S-adenosyl-L-methionine. The activity of the BBM enzyme, however, was about 2-fold higher than that of the BLM enzyme. Identification of the endogenous substrates located in the two plasma membranes by acidic gel electrophoresis in the presence of a cationic detergent revealed significant differences in the methyl-accepting proteins of both membranes. The BBM-methylated proteins had sizes of 35, 50 and 54 kDa, whereas the major BLM-methylated substrates were of 97 and 100 kDa. The enzymes showed distinct behaviour on Mono Q anion-exchange chromatography. The BBM-associated PCMT did not bind to the column, being eluted in the flow-through, whereas the BLM enzyme bound to the column and was eluted at 0.15 M NaCl. Moreover, the two enzymes had different molecular masses under both denaturing and nondenaturing conditions, the BLM PCMT migrating at an apparent molecular mass of 29 kDa, compared with 27 kDa for the BBM enzyme. Taken together, these results show the presence of two distinct L-isoaspartyl PCMTs in the plasma membranes of the kidney cortex.

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Identification of two distinct protein carboxyl methyltransferases in eucaryotic cells

Cited by 5 publications

References 13 publications

Immunochemical characterization of l-isoaspartyl-protein carboxyl methyltransferase from mammalian tissues

Immunochemical characterization of l-isoaspartyl-protein carboxyl methyltransferase from mammalian tissues

Alteration in angiotensin-converting enzyme 2 by PM₁during the development of emphysema in rats

Asymmetrical distribution of l-isoaspartyl protein carboxyl methyltransferases in the plasma membranes of rat kidney cortex

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Identification of two distinct protein carboxyl methyltransferases in eucaryotic cells

Cited by 5 publications

References 13 publications

Immunochemical characterization of l-isoaspartyl-protein carboxyl methyltransferase from mammalian tissues

Immunochemical characterization of l-isoaspartyl-protein carboxyl methyltransferase from mammalian tissues

Alteration in angiotensin-converting enzyme 2 by PM1during the development of emphysema in rats

Asymmetrical distribution of l-isoaspartyl protein carboxyl methyltransferases in the plasma membranes of rat kidney cortex

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Alteration in angiotensin-converting enzyme 2 by PM₁during the development of emphysema in rats