POGLUT2 and POGLUT3 O-glucosylate multiple EGF repeats in fibrillin-1, -2, and LTBP1 and promote secretion of fibrillin-1.

Williamson, Daniel B; Sohn, Camron J; Ito, Atsuko; Haltiwanger, Robert S

Williamson, Daniel B; Sohn, Camron J; Ito, Atsuko; Haltiwanger, Robert S.

Afiliación

Williamson DB; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA.
Sohn CJ; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA.
Ito A; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA.
Haltiwanger RS; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA. Electronic address: rhalti@uga.edu.

J Biol Chem ; 297(3): 101055, 2021 09.

Article en En | MEDLINE | ID: mdl-34411563

RESUMEN

Fibrillin-1 (FBN1) is the major component of extracellular matrix microfibrils, which are required for proper development of elastic tissues, including the heart and lungs. Through protein-protein interactions with latent transforming growth factor (TGF) ß-binding protein 1 (LTBP1), microfibrils regulate TGF-ß signaling. Mutations within the 47 epidermal growth factor-like (EGF) repeats of FBN1 cause autosomal dominant disorders including Marfan Syndrome, which is characterized by disrupted TGF-ß signaling. We recently identified two novel protein O-glucosyltransferases, Protein O-glucosyltransferase 2 (POGLUT2) and 3 (POGLUT3), that modify a small fraction of EGF repeats on Notch. Here, using mass spectral analysis, we show that POGLUT2 and POGLUT3 also modify over half of the EGF repeats on FBN1, fibrillin-2 (FBN2), and LTBP1. While most sites are modified by both enzymes, some sites show a preference for either POGLUT2 or POGLUT3. POGLUT2 and POGLUT3 are homologs of POGLUT1, which stabilizes Notch proteins by addition of O-glucose to Notch EGF repeats. Like POGLUT1, POGLUT2 and 3 can discern a folded versus unfolded EGF repeat, suggesting POGLUT2 and 3 are involved in a protein folding pathway. In vitro secretion assays using the N-terminal portion of recombinant FBN1 revealed reduced FBN1 secretion in POGLUT2 knockout, POGLUT3 knockout, and POGLUT2 and 3 double-knockout HEK293T cells compared with wild type. These results illustrate that POGLUT2 and 3 function together to O-glucosylate protein substrates and that these modifications play a role in the secretion of substrate proteins. It will be interesting to see how disease variants in these proteins affect their O-glucosylation.

Asunto(s)

Fibrilina-1/metabolismo; Fibrilina-2/metabolismo; Proteínas de Unión a TGF-beta Latente/metabolismo; Síndrome de Marfan/metabolismo; Secuencias de Aminoácidos; Fibrilina-1/química; Fibrilina-1/genética; Fibrilina-2/química; Fibrilina-2/genética; Glicosilación; Humanos; Proteínas de Unión a TGF-beta Latente/química; Proteínas de Unión a TGF-beta Latente/genética; Síndrome de Marfan/enzimología; Síndrome de Marfan/genética; Sistemas de Translocación de Proteínas; Transducción de Señal

Palabras clave

EGF repeats; O-glucose; extracellular matrix protein; glycoprotein secretion; glycosylation; mass spectrometry; protein folding

Texto completo

Añadir a Mi BVS

Imprimir

XML

PubMed Links

Buscar en Google

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Proteínas de Unión a TGF-beta Latente / Fibrilina-1 / Fibrilina-2 / Síndrome de Marfan Tipo de estudio: Prognostic_studies Límite: Humans Idioma: En Revista: J Biol Chem Año: 2021 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos

Texto completo

Añadir a Mi BVS

Imprimir

XML

PubMed Links

Buscar en Google