Assuntos
Adipose Dolorosa/metabolismo , Lipomatose/metabolismo , Doenças Raras/metabolismo , 1-Alquil-2-acetilglicerofosfocolina Esterase/sangue , Adipose Dolorosa/complicações , Adipose Dolorosa/diagnóstico por imagem , Proteína C-Reativa , Criança , HDL-Colesterol/sangue , Dislipidemias/sangue , Feminino , Humanos , Lipomatose/diagnóstico , Lipoproteínas/sangue , Dor/etiologia , Doenças Raras/complicações , Doenças Raras/diagnóstico por imagemAssuntos
Humanos , Feminino , Criança , Adipose Dolorosa/metabolismo , Doenças Raras/metabolismo , Lipomatose/metabolismo , Dor/etiologia , Proteína C-Reativa , Adipose Dolorosa/complicações , Adipose Dolorosa/diagnóstico por imagem , Doenças Raras/complicações , Doenças Raras/diagnóstico por imagem , 1-Alquil-2-acetilglicerofosfocolina Esterase/sangue , Dislipidemias/sangue , Lipomatose/diagnóstico , Lipoproteínas/sangue , HDL-Colesterol/sangueRESUMO
Ribosome biogenesis in eukaryotes is a complex process that requires the participation of several accessory proteins that are not part of the mature particle. Efl1 is a yeast GTPase required for the cytoplasmic maturation of the 60S ribosomal subunit. Together with Sdo1, the yeast ortholog of the protein mutated in the Shwachman-Diamond Syndrome (SBDS), Efl1 releases the anti-association factor Tif6 from the surface of the 60S subunit allowing the assembly of mature ribosomes. We characterized the structural content and folding stability of the Saccharomyces cerevisiae and human EFL1 GTPases, as well as their enzymatic properties alone and in the presence of Sdo1 and SBDS, respectively. The human and S. cerevisiae EFL1 GTPases are composed of a mixture of α-helices and ß-sheets. Despite being orthologs, the yeast protein elicited a non-two state thermal unfolding behavior while the human EFL1 was highly resistant to thermal denaturation. Steady-state kinetic analyses indicated slow GTP hydrolysis for both EFL1 GTPases, with kcat values of 0.4 and 0.3min(-1) and Km for GTP of 110 and 180µM respectively. In the presence of the effector proteins, their kcat values remained unaltered while the Km decreased twofold suggesting that Sdo1 and SBDS act as nucleotide exchange factors.
Assuntos
Doenças da Medula Óssea/enzimologia , Doenças da Medula Óssea/genética , Insuficiência Pancreática Exócrina/enzimologia , Insuficiência Pancreática Exócrina/genética , GTP Fosfo-Hidrolases/metabolismo , Lipomatose/enzimologia , Lipomatose/genética , Mutação , Proteínas/química , Proteínas/genética , Proteínas Ribossômicas/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , Doenças da Medula Óssea/metabolismo , Estabilidade Enzimática/genética , Insuficiência Pancreática Exócrina/metabolismo , GTP Fosfo-Hidrolases/química , Humanos , Lipomatose/metabolismo , Desdobramento de Proteína , Proteínas/metabolismo , Proteínas Ribossômicas/química , Proteínas Ribossômicas/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Síndrome de Shwachman-Diamond , TermodinâmicaRESUMO
OBJECTIVE: To characterize the endocrine phenotype of patients with Shwachman-Diamond syndrome (SDS). STUDY DESIGN: Clinically indicated endocrine screening data from 43 patients with SDS or SDS-like presentation were analyzed according to sex, age, and genetic testing. In addition to 25 patients with biallelic Shwachman-Bodian-Diamond syndrome (SBDS) gene mutations, we evaluated 18 patients with cytopenias who were receiving pancreatic enzyme replacement but were without SBDS mutation. We performed a retrospective review of growth records and clinically indicated endocrine evaluations. RESULTS: Of patients with SBDS mutations, 2 had low stimulated growth hormone levels, 2 had mildly elevated thyrotropin levels, 5 had abnormal glucose levels, and 1 had an elevated follicle-stimulating hormone level (post transplantation). In contrast, 1 patient without SBDS mutations had postprandial hyperglycemia and 3 had mildly low free thyroxine levels without short stature. Endocrine abnormalities were identified in 19% of short patients and 26% of the whole group. Of patients with SBDS mutations, 56% had a height expressed in SD units from the mean for age and sex of <-1.8, in contrast to only 12% of patients without SBDS mutations (38% of the whole group). Body mass index z score was significantly greater in the group with SBDS mutations (P<.001). CONCLUSION: Although short stature was more common in patients with SBDS mutations, no consistent endocrine phenotype was observed in patients with SDS regardless of genetic testing.