Fibroblasts degrade newly synthesised collagen within the cell before secretion

Bienkowski, Robert S.; Baum, Bruce J.; Crystal, Ronald G.

doi:10.1038/276413a0

Cited by 194 publications

(61 citation statements)

References 14 publications

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“…However, such destruction of casein is similar to that described for other secretory proteins such as collagen (Bienkowski et al, 1978), parathyrin (Morrissey & Cohn, 1979), prolactin (Shenai & Wallis, 1979) and insulin (Halban & Wollheim, 1980). It appears that secretory proteins undergo extensive intracellular degradation irrespective of whether the protein is stored intracellularly in a granular form (e.g.…”

supporting

confidence: 63%

“…Thus, for example up to 70% of newly synthesized parathyrin may be destroyed intracellularly rather than being secreted from the cell (Bienkowski et al, 1978;Shenai & Wallis, 1979;Morrissey & Cohn, 1979;Halban & Wollheim, 1980). Little is known of the fate of newly synthesized casein during its packaging into secretory vesicles in the Golgi and its transport to the plasma membrane Vol.…”

mentioning

confidence: 99%

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Extensive destruction of newly synthesized casein in mammary explants in organ culture

Hasan

White

Mayer

1982

Biochemical Journal

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1. Explants of mammary glands of mid-pregnant rabbits that had been cultured for 18 h in the presence of insulin, prolactin and cortisol were incubated at 370C for 2h in Medium 199 containing L-[4,5-3H]leucine. After a wash procedure at 40C, explants were re-incubated at 370C in fresh medium and the radioactivity of casein polypeptides isolated by isoelectric focusing (at pH4.6) was followed with time. Casein radioactivity rose during the first hour of re-incubation, but fell markedly during the subsequent hour. 2. Loss of radioactivity represented casein degradation, since less than 10% of newly synthesized casein was found in the incubation medium. 3. Such a loss of radioactivity was not due solely to hydrolysis of signal peptides, since similar results were obtained when L-[5-3H]proline, which is not part of casein signal peptides, was the radiolabelled precursor. 4. A dual-isotope experiment using L-FU-'4C]proline and N-[ 3Hlacetyl-D-mannosamine gave similar profiles of radioactivity loss from isoelectrically focused casein, indicating that degradation of mature casein was occurring. 5. Analysis of total pellet and particle-free-supernatant fractions prepared by centrifugation of explant homogenates at 1 5 000 g, for 1 h did not show loss of radioactivity on re-incubation. Total pellet-protein radioactivity remained constant, whereas total soluble-protein radioactivity increased during the 2h re-incubation period. 6. Radioactivity in a specific particle-free-supernatant polypeptide, the subunit of fatty acid synthetase, mimicked that of the total soluble protein. 7. Addition of cycloheximide (20,ug/ml) during the re-incubation period completely blocked the incorporation of radioactivity from L-[5-3H]proline into casein and the subsequent fall, indicating that observations were being made on newly synthesized casein. 8. Addition of chloroquine (50,uM) did not prevent the increase in radioactivity from L-[5-3HIproline into casein during the first hour of re-incubation, but did prevent the loss of radioactivity in the second hour. 9. The intracellular degradation of a newly synthesized milk protein is discussed in relation to the known intracellular degradation of other secretory polypeptides.

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supporting

confidence: 63%

mentioning

confidence: 99%

Extensive destruction of newly synthesized casein in mammary explants in organ culture

Hasan

White

Mayer

1982

Biochemical Journal

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“…Furthermore, the 12 h phase difference between the peaks of glycosides and pyridinolines suggests that hydroxylysine glycosides are more likely markers of both bone resorption and bone formation rather than indicating a difference in the metabolic pathways of the two classes of catabolites. In this regard, while the source of pyridinolines is undoubtedly the mature collagen, the source of GGHYL and GHYL could be also the intracellular breakdown of new synthetized procollagen demonstrated by Bienkowski et al [29] in cultured fibroblasts.…”

Section: Discussionmentioning

confidence: 99%

Urinary output of hydroxylysine glycosides and pyridinium cross‐links in detecting rat bone collagen turnover rate

Grazioli¹,

Alfano²,

Stenico³

et al. 1996

FEBS Letters

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Glucosylgalactosylhydroxylysine (GGHYL), galactosylhydroxylysine (GHYL), pyridinoline (PYD) and deoxypyridinoline (DPD) were measured in the urine (6 h serial specimens over 96 and 24 h urine specimens for 4 days) collected from four adult Sprague Dawley rats and in the femoral and tibial bone as well as in the dorsal skin of the same rats. No significant daily variations were found in the urine excretion of GGHYL, GHYL, PYD and DPD but significant diurnal variations. The GGHYL! GHYL ratio in rat urine (0.46_+ 0.1) reflected neither the bone collagen ratio (1.9 to 2.4) nor the skin collagen ratio (1.22-+ 1.07), a finding that may reflect GGHYL conversion into GHYL. The content of both pyridinolines was very low in the skin and high in the bone collagen and the urinary PYD/DPD ratio (1.46-+ 0.15) reflected essentially the bone collagen ratio (0.8-3.0). These results suggest the usefulness of measuring GGHYL, GHYL, PYD and DPD in 24 h urine specimen and, based on the inter-animal variations, the necessity to consider each animal as its own control when bone turnover needs to be monitored.

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“…After evaporation to dryness, the first one was used to measure free proline [6]. The second one was hydrolyzed by 6 M HCI and hydroxyproline was measured as an estimate of the intracellular degradation of newly synthesized procollagen [6,7].…”

Section: Fibroblastsmentioning

confidence: 99%

Stimulation of collagen synthesis in fibroblast cultures by the tripeptide‐copper complex glycyl‐L‐histidyl‐L‐lysine‐Cu²⁺

Pickart²,

et al. 1988

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Glycyl-L-histidyl-L-lysine (GHK) is a tripeptide with affinity for copper(H) ions and was isolated from human plasma.This peptide appears to play a physiological role in wound healing. We report the stimulating effect of GHK-Cu on collagen synthesis by fibroblasts. The stimulation began between IO-'2 and IO-" M, maximized at 10e9 M, and was independent of any change in cell number. The presence of a GHK triplet in the a;(I) chain of type I collagen suggests that the tripcptide might be liberated by proteases at the site of a wound and exert in situ healing effects.

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Fibroblasts degrade newly synthesised collagen within the cell before secretion

Cited by 194 publications

References 14 publications

Extensive destruction of newly synthesized casein in mammary explants in organ culture

Extensive destruction of newly synthesized casein in mammary explants in organ culture

Urinary output of hydroxylysine glycosides and pyridinium cross‐links in detecting rat bone collagen turnover rate

Stimulation of collagen synthesis in fibroblast cultures by the tripeptide‐copper complex glycyl‐L‐histidyl‐L‐lysine‐Cu²⁺

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Fibroblasts degrade newly synthesised collagen within the cell before secretion

Cited by 194 publications

References 14 publications

Extensive destruction of newly synthesized casein in mammary explants in organ culture

Extensive destruction of newly synthesized casein in mammary explants in organ culture

Urinary output of hydroxylysine glycosides and pyridinium cross‐links in detecting rat bone collagen turnover rate

Stimulation of collagen synthesis in fibroblast cultures by the tripeptide‐copper complex glycyl‐L‐histidyl‐L‐lysine‐Cu2+

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Stimulation of collagen synthesis in fibroblast cultures by the tripeptide‐copper complex glycyl‐L‐histidyl‐L‐lysine‐Cu²⁺