FAM20A binds to and regulates FAM20C localization

Ohyama, Yoshio; Lin, Ju-Hsien; Govitvattana, Nattanan; Lin, I-Ping; Venkitapathi, Sundharamani; Alamoudi, Ahmed; Husein, Dina; An, Chunying; Hotta, Hak; Kaku, Masaru; Mochida, Yoshiyuki

doi:10.1038/srep27784

Cited by 39 publications

(58 citation statements)

References 40 publications

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“…By using this electrophoretic pattern as a readout for OPN phosphorylation, we also identify the Golgi apparatus as the compartment where OPN locates preferentially and is subjected to this posttranslational modification. 41 Unique biochemical characteristics displayed by Fam20C are the S-x-E/pS motif as critical determinant for substrate phosphorylation, and the insensitivity to the broad-spectrum protein kinase inhibitor staurosporine. Fam20C has been classified as a Golgi protein kinase, and until 2012 it was known as GCK.…”

Section: Discussionmentioning

confidence: 99%

“…That OPN is defined as a secreted phosphoprotein and has been already described as a substrate for Fam20C, 26 an essential player in generating the entire phosphosecretome, 46 lead us to point to this enzyme as responsible for the phosphorylation of OPN and as an indirect driver of fibrogenesis. 26,41,43,47 All these features are exploited in the present study to characterize Fam20C activity in the Golgi apparatus by performing highly specific kinase assays with the use of a peptide containing the above consensus sequence in the presence of elevated concentrations of staurosporine. 25,26 Indeed, it was recognized as the genuine protein kinase phosphorylating casein in lactating mammary gland, by contrast with casein kinase I and II, which had been characterized by their ability to phosphorylate casein as a surrogate substrate.…”

Section: Discussionmentioning

confidence: 99%

“…40,41 This prompted us to explore the possibility that the formation of this heterodimer could also account for the increase of Fam20C activity and contribute to liver fibrogenesis. 40,41 This prompted us to explore the possibility that the formation of this heterodimer could also account for the increase of Fam20C activity and contribute to liver fibrogenesis.…”

Section: Fam20c Activation Depends On the Formation Of A Golgi-resimentioning

confidence: 99%

“…First, we compared the protein level of Fam20C and Fam20A in the Golgienriched fractions of livers of sham-operated rats to those of rats subjected to BDL by Wb analysis with relevant antibodies. 40,41 To investigate this aspect, soluble Golgi extracts from livers of sham-operated rats and liver of rats on day 15 after BDL underwent size exclusion chromatography on a Superdex 200 column, and the resulting fractions were monitored for Fam20C activity and the elution profile of Fam20C and Fam20A. Furthermore, Wb analysis of Fam20C immunoprecipitates from the Golgi-enriched fractions with anti-Fam20A and anti-Fam20C antibodies revealed that Fam20A interacted more tightly with Fam20C in samples from livers developing fibrosis relative to normal livers ( Figure 4A), further supporting the hypothesis of a relationship between the increase in the activity of Fam20C in the fibrotic liver and the formation of the heterodimer.…”

Section: Fam20c Activation Depends On the Formation Of A Golgi-resimentioning

confidence: 99%

“…To do so, we isolated Fam20C from the Golgi fraction of fibrotic livers on day 15 after BDL by a procedure previously developed to purify Fam20C itself (at the time referred to as G-CK) from the lactating mammary gland, 41,42 which would be used to phosphorylate recombinant OPN (rOPN) in vitro. To do so, we isolated Fam20C from the Golgi fraction of fibrotic livers on day 15 after BDL by a procedure previously developed to purify Fam20C itself (at the time referred to as G-CK) from the lactating mammary gland, 41,42 which would be used to phosphorylate recombinant OPN (rOPN) in vitro.…”

Section: Phosphorylation Is Dispensable For the Action Of Opn As A mentioning

confidence: 99%

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Fam20C‐mediated phosphorylation of osteopontin is critical for its secretion but dispensable for its action as a cytokine in the activation of hepatic stellate cells in liver fibrogenesis

et al. 2019

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Amedeo Carraro and Anna Maria Brunati are co-senior authors.Abbreviations: BDL, bile duct ligation; CK1, casein kinase1; ECM, extracellular matrix; ER, endoplasmic reticulum; Fam20A, family with sequence similarity 20, member A; Fam20C, family with sequence similarity 20, member C; F/P, FBS combined with PDGF; FBS, fetal bovine serum; GRP94, glucose related protein 94; GRP78/BiP, glucose related protein78; HSCs, hepatic stellate cells; OPN, osteopontin; PDI, protein disulfide isomerase; PDGF, platelet-derived growth factor; PTMs, posttranslational modifications; qRT-PCR, quantitative reverse transcription-polymerase chain reaction; RGD, Arg-Gly-Asp; SIBLING, small-integrin-binding ligand N-linked glycoprotein; Wb, Western blot; α-SMA, alpha-smooth muscle actin. AbstractOsteopontin (OPN) is a phosphoglycoprotein secreted into the extracellular matrix upon liver injury, acting as a cytokine stimulates the deposition of fibrillary collagen in liver fibrogenesis. In livers of mice subjected to bile duct ligation (BDL) and in cultured activated hepatic stellate cells (HSCs), we show that OPN, besides being overexpressed, is substantially phosphorylated by family with sequence similarity 20, member C (Fam20C), formerly known as Golgi casein kinase (G-CK), which is exclusively resident in the Golgi apparatus. In both experimental models, Fam20C becomes overactive when associated with a 500-kDa multiprotein complex, as compared with the negligible activity in livers of sham-operated rats and in quiescent HSCs. Fam20C knockdown not only confirmed the role of Fam20C itself in OPN phosphorylation, but also revealed that phosphorylation was essential for OPN secretion. However, OPN acts as a fibrogenic factor independently of its phosphorylation state, as demonstrated by the increased expression of Collagen-I by HSCs incubated with either a phosphorylated or nonphosphorylated form of recombinant OPN. Collectively, our results confirm that OPN promotes liver fibrosis and highlight Fam20C as a novel factor driving this process by favoring OPN secretion from HSCs, opening new avenues for deciphering yet unidentified mechanisms underlying liver fibrogenesis. K E Y W O R D Sbile duct ligation, Golgi apparatus, hepatic stellate cells, osteopontin, phosphorylation

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Fam20c Activation Depends On the Formation Of A Golgi-resimentioning

confidence: 99%

Section: Fam20c Activation Depends On the Formation Of A Golgi-resimentioning

confidence: 99%

Section: Phosphorylation Is Dispensable For the Action Of Opn As A mentioning

confidence: 99%

See 3 more Smart Citations

Fam20C‐mediated phosphorylation of osteopontin is critical for its secretion but dispensable for its action as a cytokine in the activation of hepatic stellate cells in liver fibrogenesis

et al. 2019

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Thinking outside of the cell: Secreted protein kinases in bacteria, parasites, and mammals

2019

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Previous decades have seen an explosion in our understanding of protein kinase function in human health and disease. Hundreds of unique kinase structures have been solved, allowing us to create generalized rules for catalysis, assign roles of communities within the catalytic core, and develop specific drugs for targeting various pathways. Although our understanding of intracellular kinases has developed at a fast rate, our exploration into extracellular kinases has just begun. In this review, we will cover the secreted protein kinase families found in humans, bacteria, and parasites. © 2019 IUBMB Life, 71(6):749–759, 2019

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Raine Syndrome (OMIM #259775), Caused By FAM20C Mutation, Is Congenital Sclerosing Osteomalacia With Cerebral Calcification (OMIM 259660)

Whyte

McAlister

Fallon

et al. 2016

Journal of Bone and Mineral Research

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In 1985, we briefly reported infant sisters with a unique, lethal, autosomal recessive disorder designated congenital sclerosing osteomalacia with cerebral calcification. In 1986, this condition was entered into Mendelian Inheritance In Man (MIM) as osteomalacia, sclerosing, with cerebral calcification (MIM 259660). However, no attestations followed. Instead, in 1989 Raine and colleagues published an affected neonate considering unprecedented the striking clinical and radiographic features. In 1992, "Raine syndrome" entered MIM formally as osteosclerotic bone dysplasia, lethal (MIM #259775). In 2007, the etiology emerged as loss-of-function mutation of FAM20C that encodes family with sequence similarity 20, member C. FAM20C is highly expressed in embryonic calcified tissues and encodes a kinase (dentin matrix protein 4) for most of the secreted phosphoproteome including FGF23, osteopontin, and other regulators of skeletal mineralization. Herein, we detail the clinical, radiological, biochemical, histopathological, and FAM20C findings of our patients. Following premortem tetracycline labeling, the proposita's non-decalcified skeletal histopathology after autopsy indicated no rickets but documented severe osteomalacia. Archival DNA revealed the sisters were compound heterozygotes for a unique missense mutation and a novel deletion in FAM20C. Individuals heterozygous for the missense mutation seemed to prematurely fuse their metopic suture and develop a metopic ridge sometimes including trigonocephaly. Our findings clarify FAM20C's role in hard tissue formation and mineralization, and show that Raine syndrome is congenital sclerosing osteomalacia with cerebral calcification. © 2016 American Society for Bone and Mineral Research.

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FAM20A binds to and regulates FAM20C localization

Cited by 39 publications

References 40 publications

Fam20C‐mediated phosphorylation of osteopontin is critical for its secretion but dispensable for its action as a cytokine in the activation of hepatic stellate cells in liver fibrogenesis

Fam20C‐mediated phosphorylation of osteopontin is critical for its secretion but dispensable for its action as a cytokine in the activation of hepatic stellate cells in liver fibrogenesis

Thinking outside of the cell: Secreted protein kinases in bacteria, parasites, and mammals

Raine Syndrome (OMIM #259775), Caused By FAM20C Mutation, Is Congenital Sclerosing Osteomalacia With Cerebral Calcification (OMIM 259660)

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