The CrebA/Creb3-like transcription factors are major and direct regulators of secretory capacity.
Secretion occurs in all cells, with relatively low levels in most cells and extremely high levels in specialized secretory cells, such as those of the pancreas, salivary, and mammary glands. How secretory capacity is selectively up-regulated in specialized secretory cells is unknown. Here, we find that the CrebA/Creb3-like family of bZip transcription factors functions to up-regulate expression of both the general protein machinery required in all cells for secretion and of cell type-specific secreted proteins. Drosophila CrebA directly binds the enhancers of secretory pathway genes and is both necessary and sufficient to activate expression of every secretory pathway component gene examined thus far. Microarray profiling reveals that CrebA also up-regulates expression of genes encoding cell type-specific secreted components. Finally, we found that the human CrebA orthologues, Creb3L1 and Creb3L2, have the ability to up-regulate the secretory pathway in nonsecretory cell types.
Department of Cell Biology, The Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
Rebecca M
RM
Fox
Caitlin D
CD
Hanlon
Deborah J
DJ
Andrew
D000818:Animals; D050976:Basic-Leucine Zipper Transcription Factors / Q000378:metabolism; D016384:Consensus Sequence / Q000235:genetics; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D051699:Cyclic AMP Response Element-Binding Protein A / Q000235:genetics / Q000378:metabolism*; D004330:Drosophila / Q000196:embryology / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004742:Enhancer Elements, Genetic / Q000235:genetics; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D017344:Genes, Insect / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D012469:Salivary Glands / Q000166:cytology / Q000378:metabolism*; D015854:Up-Regulation
D050976:Basic-Leucine Zipper Transcription Factors; C485618:CREB3L1 protein, human; C518609:CREB3L2 protein, human; C073555:CrebA protein, Drosophila; D017362:Cyclic AMP Response Element-Binding Protein; D051699:Cyclic AMP Response Element-Binding Protein A; D029721:Drosophila Proteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins