CTP:cholinephosphate cytidylyltransferase in human and rat lung: Association in vitro with cytoskeletal actin
CTP:cholinephosphate cytidylyltransferase in human and rat lung: Association in vitro with cytoskeletal actin
CTP:cholinephosphate cytidylyltransferase activities were compared in saline homogenates of immature fetal (15-16 weeks gestation) and adult human lung. There were no differences in subcellular enzyme distribution, in Vmax activity, or in the phosphatidylglycerol-mediated stimulation of soluble enzyme activity. These results provide no support for a developmental translocation of cytidylyltransferase from a cytosolic to a microsomal location in human lung, such as that proposed to accompany the maturation of pulmonary surfactant phosphatidylcholine biosynthesis in rat. Soluble cytidylyltransferase activity from human but not rat lung was increased after manipulation in vitro. Resolution of human H form (greater than 10(3) kDa) and L form (200 kDa) enzyme by gel filtration led to an activity increase of 200%. Incubation at 37 degrees C for 2 h increased soluble enzyme recovery, although prior centrifugal removal of generated actin-rich aggregates was necessary in adult lung fractions. In contrast, 85% of soluble rat lung cytidylyltransferase was actin aggregate-associated after incubation. The apparent heteroassociation of rat and human lung enzyme with actin in the presence of poly(ethylene glycol) at 4 degrees C strongly suggested close in vitro and potential in vivo linkage. A partial co-purification of adult human lung cytidylyltransferase with actin was also consistent with this idea. We propose that some reported cytidylyltransferase translocation phenomena may be mediated by cytoskeletal interactions in vitro.
19-26
Hunt, A.N.
95a3e223-da96-40e7-b47d-27dce014e305
Normand, I.C.S.
93c0816b-c5a0-4abf-b4c9-b4cf377aae48
Postle, A.D.
0fa17988-b4a0-4cdc-819a-9ae15c5dad66
12 March 1990
Hunt, A.N.
95a3e223-da96-40e7-b47d-27dce014e305
Normand, I.C.S.
93c0816b-c5a0-4abf-b4c9-b4cf377aae48
Postle, A.D.
0fa17988-b4a0-4cdc-819a-9ae15c5dad66
Hunt, A.N., Normand, I.C.S. and Postle, A.D.
(1990)
CTP:cholinephosphate cytidylyltransferase in human and rat lung: Association in vitro with cytoskeletal actin.
Biochimica et Biophysica Acta - Lipids and Lipid Metabolism, 1043 (1), .
(doi:10.1016/0005-2760(90)90105-7).
Abstract
CTP:cholinephosphate cytidylyltransferase activities were compared in saline homogenates of immature fetal (15-16 weeks gestation) and adult human lung. There were no differences in subcellular enzyme distribution, in Vmax activity, or in the phosphatidylglycerol-mediated stimulation of soluble enzyme activity. These results provide no support for a developmental translocation of cytidylyltransferase from a cytosolic to a microsomal location in human lung, such as that proposed to accompany the maturation of pulmonary surfactant phosphatidylcholine biosynthesis in rat. Soluble cytidylyltransferase activity from human but not rat lung was increased after manipulation in vitro. Resolution of human H form (greater than 10(3) kDa) and L form (200 kDa) enzyme by gel filtration led to an activity increase of 200%. Incubation at 37 degrees C for 2 h increased soluble enzyme recovery, although prior centrifugal removal of generated actin-rich aggregates was necessary in adult lung fractions. In contrast, 85% of soluble rat lung cytidylyltransferase was actin aggregate-associated after incubation. The apparent heteroassociation of rat and human lung enzyme with actin in the presence of poly(ethylene glycol) at 4 degrees C strongly suggested close in vitro and potential in vivo linkage. A partial co-purification of adult human lung cytidylyltransferase with actin was also consistent with this idea. We propose that some reported cytidylyltransferase translocation phenomena may be mediated by cytoskeletal interactions in vitro.
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Published date: 12 March 1990
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Local EPrints ID: 467428
URI: http://eprints.soton.ac.uk/id/eprint/467428
PURE UUID: 88b15421-8129-4478-aeb6-e56e7463054e
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Date deposited: 08 Jul 2022 16:35
Last modified: 17 Mar 2024 02:41
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Author:
A.N. Hunt
Author:
I.C.S. Normand
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