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Proceedings of the National Academy of... Jan 2024Newly synthesized secretory proteins are exported from the endoplasmic reticulum (ER) at specialized subcompartments called exit sites (ERES). Cargoes like procollagen...
Newly synthesized secretory proteins are exported from the endoplasmic reticulum (ER) at specialized subcompartments called exit sites (ERES). Cargoes like procollagen are too large for export by the standard COPII-coated vesicle of 60 nm average diameter. We have previously suggested that procollagen is transported from the ER to the next secretory organelle, the ER-Golgi intermediate compartment (ERGIC), in TANGO1-dependent interorganelle tunnels. In the theoretical model presented here, we suggest that intrinsically disordered domains of TANGO1 in the ER lumen induce an entropic contraction, which exerts a force that draws procollagen toward the ERES. Within this framework, molecular gradients of pH and/or HSP47 between the ER and ERGIC create a force in the order of tens of femto-Newtons. This force is substantial enough to propel procollagen from the ER at a speed of approximately 1 nm · s. This calculated speed and the quantities of collagen secreted are similar to its observed physiological secretion rate in fibroblasts, consistent with the proposal that ER export is the rate-limiting step for procollagen secretion. Hence, the mechanism we propose is theoretically adequate to explain how cells can utilize molecular gradients and export procollagens at a rate commensurate with physiological needs.
Topics: Procollagen; Protein Transport; Collagen; Biological Transport; Endoplasmic Reticulum; Golgi Apparatus; COP-Coated Vesicles
PubMed: 38147551
DOI: 10.1073/pnas.2310404120 -
American Journal of Transplantation :... Mar 2023Acute rejection (AR) is an important factor that leads to poor prognosis after liver transplantation (LT). Macrophage M1-polarization is an important mechanism in AR...
Acute rejection (AR) is an important factor that leads to poor prognosis after liver transplantation (LT). Macrophage M1-polarization is an important mechanism in AR development. MicroRNAs play vital roles in disease regulation; however, their effects on macrophages and AR remain unclear. In this study, rat models of AR were established following LT, and macrophages and peripheral blood mononuclear cells were isolated from rats and humans, respectively. We found miR-449a expression to be significantly reduced in macrophages and peripheral blood mononuclear cells. Overexpression of miR-449a not only inhibited the M1-polarization of macrophages in vitro but also improved the AR of transplant in vivo. The mechanism involved inhibiting the noncanonical nuclear factor-kappaB (NF-κB) pathway. We identified procollagen-lysine1,2-oxoglutarate5-dioxygenase 1 (PLOD1) as a target gene of miR-449a, which could reverse miR-449a's inhibition of macrophage M1-polarization, amelioration of AR, and inhibition of the NF-κB pathway. Overall, miR-449a inhibited the NF-κB pathway in macrophages through PLOD1 and also inhibited the M1-polarization of macrophages, thus attenuating AR after LT. In conclusion, miR-449a and PLOD1 may be new targets for the prevention and mitigation of AR.
Topics: Animals; Humans; Rats; Leukocytes, Mononuclear; Liver Transplantation; Macrophages; MicroRNAs; NF-kappa B; Procollagen
PubMed: 36695693
DOI: 10.1016/j.ajt.2022.12.009 -
Nature Communications Apr 2023Bulky cargos like procollagens, apolipoproteins, and mucins exceed the size of conventional COPII vesicles. During evolution a process emerged in metazoans,...
Bulky cargos like procollagens, apolipoproteins, and mucins exceed the size of conventional COPII vesicles. During evolution a process emerged in metazoans, predominantly governed by the TANGO1 protein family, that organizes cargo at the exit sites of the endoplasmic reticulum and facilitates export by the formation of tunnel-like connections between the ER and Golgi. Hitherto, cargo-recognition appeared to be mediated by an SH3-like domain. Based on structural and dynamic data as well as interaction studies from NMR spectroscopy and microscale thermophoresis presented here, we show that the luminal cargo-recognition domain of TANGO1 adopts a new functional fold for which we suggest the term MOTH (MIA, Otoraplin, TALI/TANGO1 homology) domain. These MOTH domains, as well as an evolutionary intermediate found in invertebrates, constitute a distinct domain family that emerged from SH3 domains and acquired the ability to bind collagen.
Topics: Protein Transport; src Homology Domains; Collagen; Procollagen; Golgi Apparatus
PubMed: 37080980
DOI: 10.1038/s41467-023-37705-4 -
Genes May 2022Background: The relationship between pelvic organ prolapse (POP), an aging-related disease, and the senescence-related protein mitofusin 2 (Mfn2) has rarely been...
Background: The relationship between pelvic organ prolapse (POP), an aging-related disease, and the senescence-related protein mitofusin 2 (Mfn2) has rarely been studied. The aim of the present study was to explore the therapeutic effects of the downregulation of Mfn2 expression by stem cells on POP through animal experiments. Methods: First, a rat POP model was constructed by ovariectomy and traction. The rats in the non-pelvic organ prolapse (NPOP) and POP groups were divided into four groups for negative controls (N1−N4, N1: NPOP-normal saline; N2: NPOP-untransfected stem cells; N3: NPOP-short hairpin negative control (NPOP-sh-NC); N4: NPOP-short hairpin-Mfn2 (NPOP-sh-Mfn2)), and four groups for prolapse (P1−P4, P1: POP-normal saline; P2: POP-untransfected stem cells; P3: POP-sh-NC; P4: POP-sh-Mfn2), respectively. Stem cells were then cultured and isolated. The expression of Mfn2 was inhibited by lentivirus transfection, and the stem cells were injected into the uterosacral ligament of the rats in each group. The expression levels of Mfn2 and procollagen 1A1/1A2/3A1 in the uterosacral ligaments of the rats were observed at 0, 7, 14, and 21 days after injection. Results: Compared to the rats in the NPOP group, the POP rats had significant prolapse. The Mfn2 expression in the uterosacral ligaments of the POP rats was significantly increased (p < 0.05, all), and the expression of procollagen 1A1/1A2/3A1 was significantly decreased (p < 0.001, all). The POP rat model maintained the same trend after 21 days (without stem cell injection). At day 14, compared to the rats in the N1 group, the Mfn2 expression in the uterosacral ligament of the rats in the N4 group was significantly decreased (p < 0.05, all), and the expression of procollagens was significantly increased (p < 0.05, all). Similarly, compared to the rats in the P1 group, the Mfn2 expression in the uterosacral ligament of the rats in the P4 group was significantly decreased (p < 0.05, all), and the expression of procollagens was significantly increased (p < 0.05, all). Similarly, on day 21, the Mfn2 mRNA and protein expression in the uterosacral ligament of the POP and NPOP rats was significantly decreased (p < 0.05, all), and the expression of procollagens was significantly increased (p < 0.05, all) in the rats in the sh-Mfn2 group (N4, P4) compared to the rats in the saline group (N1, P1). Conclusions: The downregulation of Mfn2 expression by stem cells decreased the expression of Mfn2 and increased the expression of procollagen1A1/1A2/3A1 in the uterosacral ligament of the POP rats; this effect was significant 14−21 days after the injection. Thus, Mfn2 may be a new target for POP control.
Topics: Animals; Down-Regulation; Female; GTP Phosphohydrolases; Hydrolases; Ligaments; Mesenchymal Stem Cells; Mitochondrial Proteins; Pelvic Organ Prolapse; Postmenopause; Procollagen; Rats; Saline Solution
PubMed: 35627214
DOI: 10.3390/genes13050829 -
Structure (London, England : 1993) Oct 2018In this issue of Structure, Pulido et al. (2018) determine the crystal structure of procollagen C-proteinase enhancer-1 (PCPE-1)/procollagen III complex and identify...
In this issue of Structure, Pulido et al. (2018) determine the crystal structure of procollagen C-proteinase enhancer-1 (PCPE-1)/procollagen III complex and identify that PCPE-1 unwinds the stalk of the procollagen III trimer, liberating a single chain to facilitate binding and cleavage by BMP-1 proteinases for subsequent fibrillar collagen assembly.
Topics: Bone Morphogenetic Protein 1; Extracellular Matrix Proteins; Glycoproteins; Procollagen
PubMed: 30282017
DOI: 10.1016/j.str.2018.09.003 -
The Journal of Biological Chemistry Aug 1982The endodermal cell line PF-HR9, derived from the murine teratocarcinoma cell line PCC4-F, was grown as monolayers and as cell clusters called embryoid bodies....
The endodermal cell line PF-HR9, derived from the murine teratocarcinoma cell line PCC4-F, was grown as monolayers and as cell clusters called embryoid bodies. Procollagen IV and laminin were isolated from both kinds of culture media. Antibodies specific to collagen IV and to laminin demonstrated these materials in association with the cells and in the culture media. The procollagen IV consisted of pro alpha 1 IV and pro alpha 2 IV chains and gave a circular dichroic spectrum characteristic for collagen helices, with thermal transitions at 40, 44, and 51 degrees C. The molecules were visualized electron microscopically after rotary shadowing. Laminin showed the characteristic beaded cross-appearance, and procollagen IV was a 434 +/- 12-nm long linear thread containing a 17-nm carboxyl-terminal knob. The 7% of collagen helix with Tm = 51 degrees C corresponds to about a 30-nm length of the molecule and is probably that section of the amino end through which several procollagen IV molecules form a junctional complex. Several noncovalent associations of procollagen IV molecules were demonstrated by velocity sedimentation and electron microscopy of concentrated culture media, specifically associations of two and four procollagen IV molecules through their amino ends and dimers linked at their carboxyl ends. The results show that procollagen IV molecules associate noncovalently into the components which others have isolated from basement membranes and strongly support a network model of these supramolecular assemblies.
Topics: Animals; Cell Line; Centrifugation, Density Gradient; Chemical Phenomena; Chemistry; Circular Dichroism; Endoderm; Glycoproteins; Hot Temperature; Immunologic Techniques; Laminin; Macromolecular Substances; Mice; Microscopy, Electron; Neoplasm Proteins; Procollagen; Teratoma
PubMed: 7050102
DOI: No ID Found -
European Journal of Sport Science May 2020Intermittent exercise might be an efficient means of exercise for improving bone strength and quality. The aim of our study was to examine the effect of intermittent...
Intermittent exercise might be an efficient means of exercise for improving bone strength and quality. The aim of our study was to examine the effect of intermittent running on bone turnover markers using altered exercise-to-rest intervals. Twelve males completed one control (no exercise), and three, 45-min intermittent protocols (5, 20, and 80 s intervals) matched for distance and speed. Fasted venous blood samples were collected at baseline, 1, 2 and 24 h post-exercise. Carboxyterminal crosslinked telopeptide (CTX-I) and procollagen type 1 amino-terminal propeptide (P1NP) were used as markers of bone resorption and formation. After adjustment for baseline, CTX-I concentration at 1 h was higher (very likely to most likely small) for 5 s (30.2%; ±90% confidence limits: 10%), 20 s (2.9.0%; ±10%) and 80 s (32.0%; ±10%) compared to control. The very likely small effect remained for 5 s at 2 h (30.2%; ±15%). The effect for 20 and 80 s was possibly trivial and possibly small/possibly trivial (∼14.5%; ±∼15%). Differences in P1NP concentrations were likely to very likely trivial (∼7.4%; ±∼7.6%). Circulating CTX-I concentration is affected acutely by intermittent running with short-interval (5 s) intermittent loading resulting in a prolonged attenuation in circadian rhythm of CTX-I up to 2 h that was not demonstrated as clearly by longer intervals despite matched internal and external training load.
Topics: Adolescent; Adult; Biomarkers; Bone Remodeling; Collagen Type I; Healthy Volunteers; Humans; Male; Peptide Fragments; Peptides; Procollagen; Running; Young Adult
PubMed: 31322477
DOI: 10.1080/17461391.2019.1646811 -
European Journal of Cell Biology Apr 2010Bone morphogenetic protein (BMP)-2 and transforming growth factor (TGF)-beta1 are multifunctional cytokines both proposed as stimulants for cartilage repair. Thus it is...
Bone morphogenetic protein (BMP)-2 and transforming growth factor (TGF)-beta1 are multifunctional cytokines both proposed as stimulants for cartilage repair. Thus it is crucial to closely examine and compare their effects on the expression of key markers of the chondrocyte phenotype, at the gene and protein level. In this study, the expression of alpha 10 and alpha 11 integrin subunits and the IIA/IIB spliced forms of type II procollagen have been monitored for the first time in parallel in the same in vitro model of mouse chondrocyte dedifferentiation/redifferentiation. We demonstrated that TGF-beta1 stimulates the expression of the non-chondrogenic form of type II procollagen, IIA isoform, and of a marker of mesenchymal tissues, i.e. the alpha 11 integrin subunit. On the contrary, BMP-2 stimulates the cartilage-specific form of type II procollagen, IIB isoform, and a specific marker of chondrocytes, i.e. the alpha 10 integrin subunit. Collectively, our results demonstrate that BMP-2 has a better capability than TGF-beta1 to stimulate chondrocyte redifferentiation and reveal that the relative expressions of type IIB to type IIA procollagens and alpha 10 to alpha 11 integrin subunits are good markers to define the differentiation state of chondrocytes. In addition, adenoviral expression of Smad6, an inhibitor of BMP canonical Smad signaling, did not affect expression of total type II procollagen or the ratio of type IIA and type IIB isoforms in mouse chondrocytes exposed to BMP-2. This result strongly suggests that signaling pathways other than Smad proteins are involved in the effect of BMP-2 on type II procollagen expression.
Topics: Animals; Bone Morphogenetic Protein 2; Cell Differentiation; Cells, Cultured; Chondrocytes; Collagen Type II; Integrin alpha Chains; Mice; Procollagen; Transforming Growth Factor beta1
PubMed: 20129696
DOI: 10.1016/j.ejcb.2009.10.018 -
The American Journal of Pathology Jan 1987Serum assays of procollagen peptides have been suggested as useful clinical indicators of hepatic fibrogenesis. To evaluate these assays in an experimental situation,...
Serum assays of procollagen peptides have been suggested as useful clinical indicators of hepatic fibrogenesis. To evaluate these assays in an experimental situation, the carbon tetrachloride model of hepatic fibrosis was produced in the rat. With affinity-purified antibodies, ELISA assays were developed and used for detecting nanogram quantities of the aminopropeptides of Types I and III procollagen (pro-I and pro-III) in rat serum. Serum SGPT levels were also determined. Routine histologic staining, as well as immunofluorescent staining for localization of Types I, III, and IV collagen and the aminopropeptides of Types I and III procollagen were performed on corresponding livers. It was found that serum pro-III levels were elevated after 45 and 70 days of treatment (28 +/- 15.2 ng/ml and 21 +/- 3.4 ng/ml, respectively) but returned to normal levels after 90 days of treatment (less than 3 ng/ml). Serum pro-I levels were elevated after 45 days of treatment (1028 +/- 504 ng/ml) but were normal at 70 and 90 days of treatment. Serum SGPT values were elevated at 45 and 70 days of treatment but were normal at 90 days of treatment. The decline in serum pro-III levels appeared to parallel the noted decline in SGPT values. Linear regression analysis revealed a good correlation between pro-III levels and histologic inflammation (r = 0.886) but a poor correlation between pro-III levels and histologic fibrosis (r = 0.116). Immunohistochemistry revealed that the pro-III antigen persists extracellularly for at least 45 days. Therefore, serum assays of pro-III might reflect extracellular collagen degradation as well as active collagen secretion. This would limit the clinical utility of the pro-III assay as an unequivocal marker of active hepatic collagen deposition.
Topics: Animals; Blood Chemical Analysis; Carbon Tetrachloride; Enzyme-Linked Immunosorbent Assay; Female; Histocytochemistry; Immunochemistry; Liver; Liver Cirrhosis, Experimental; Peptides; Procollagen; Rats; Rats, Inbred Strains; Staining and Labeling
PubMed: 2433943
DOI: No ID Found -
The Journal of Investigative Dermatology Jul 1982Collagen synthesis is a complex orchestration of intracellular and extracellular events. In addition to synthesis of the polypeptide chains more than a dozen...
Collagen synthesis is a complex orchestration of intracellular and extracellular events. In addition to synthesis of the polypeptide chains more than a dozen modifications of the molecule occur; most of these are enzymatic and specific for collagen. Regulational control of collagen synthesis promises to be equally complex. Examples are described to 4 specific regulatory influences. Ascorbic acid markedly stimulates collagen synthesis without affecting synthesis of other proteins. This effect appears to be unrelated to its cofactor roles for hydroxylation of lysine and proline. Glucocorticoids at microM concentration specifically inhibit collagen synthesis. Tissues treated with glucocorticoids have diminished levels of mRNA for collagen. During collagen synthesis the aminoterminal propeptide of procollagen is cleaved by a specific protease. This peptide appears to be a feedback inhibitor of collagen synthesis. This effect can be demonstrated in cells and in cell-free synthesizing systems. A membrane receptor system may permit the peptide to be recognized and subsequently act as a translational control mechanism. Viral transformation of fibroblasts results in selectively decreased synthesis of collagen. Levels of cytoplasmic and nuclear mRNA are likewise selectively diminished consistent with transcriptional control.
Topics: Animals; Ascorbic Acid; Cattle; Cell Transformation, Viral; Cells, Cultured; Chick Embryo; Collagen; Fibroblasts; Glucocorticoids; Humans; Peptide Fragments; Procollagen; Rats; Skin
PubMed: 7086193
DOI: 10.1111/1523-1747.ep12545835