Human Molecular Genetics Advance Access originally published online on July 14, 2009
Human Molecular Genetics 2009 18(19):3684-3695; doi:10.1093/hmg/ddp316
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Shwachman-Bodian Diamond syndrome is a multi-functional protein implicated in cellular stress responses
1 Program in Genetics and Genome Biology, Research Institute, The Hospital for Sick Children, Toronto, Canada, 2 Department of Medical Informatics, 3 Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA and 4 Department of Molecular Genetics, University of Toronto, Toronto, Canada
* To whom correspondence should be addressed at: Program in Genetics and Genome Biology, The Hospital for Sick Children, 101 College Street, East Tower, Toronto, ON, Canada M5G 1L7. Tel: +1 4168137095; Fax: +1 4168134931; Email: j.rommens{at}utoronto.ca
Received April 10, 2009; Revised June 18, 2009; Accepted July 7, 2009
Shwachman-Diamond syndrome (SDS; OMIM 260400 [OMIM] ) results from loss-of-function mutations in the Shwachman-Bodian Diamond syndrome (SBDS) gene. It is a multi-system disorder with clinical features of exocrine pancreatic dysfunction, skeletal abnormalities, bone marrow failure and predisposition to leukemic transformation. Although the cellular functions of SBDS are still unclear, its yeast ortholog has been implicated in ribosome biogenesis. Using affinity capture and mass spectrometry, we have developed an SBDS-interactome and report SBDS binding partners with diverse molecular functions, notably components of the large ribosomal subunit and proteins involved in DNA metabolism. Reciprocal co-immunoprecipitation confirmed the interaction of SBDS with the large ribosomal subunit protein RPL4 and with DNA-PK and RPA70, two proteins with critical roles in DNA repair. Function for SBDS in response to cellular stresses was implicated by demonstrating that SBDS-depleted HEK293 cells are hypersensitive to multiple types of DNA damage as well as chemically induced endoplasmic reticulum stress. Furthermore, using multiple routes to impair translation and mimic the effect of SBDS-depletion, we show that SBDS-dependent hypersensitivity of HEK293 cells to UV irradiation can be distinguished from a role of SBDS in translation. These results indicate functions of SBDS beyond ribosome biogenesis and may provide insight into the poorly understood cancer predisposition of SDS patients.