The conserved transmembrane protein TMEM-39 coordinates with COPII to promote collagen secretion and regulate ER stress response

• Published in: PLoS genetics 2021-02, Vol.17 (2), p.e1009317-e1009317
• Main Authors: Zhang, Zhe, Luo, Shuo, Barbosa, Guilherme Oliveira, Bai, Meirong, Kornberg, Thomas B, Ma, Dengke K
• Format: Article
• Language: English
• Subjects: Animals; Biology and life sciences; Cell death; Cellular stress response; Collagen; CRISPR; Electron microscopy; Gel electrophoresis; Genes; Genomes; Heat shock proteins; Histones; Microscopy; Morphology; Mutants; Phenotypes; Physical Sciences; Protein folding; Proteins; Research and Analysis Methods; RNA-mediated interference; Secretion; Sodium lauryl sulfate; Transcription; Transmembrane proteins; Worms
• ISSN: 1553-7404; 1553-7390; 1553-7404
• DOI: 10.1371/JOURNAL.PGEN.1009317

Dysregulation of collagen production and secretion contributes to aging and tissue fibrosis of major organs. How procollagen proteins in the endoplasmic reticulum (ER) route as specialized cargos for secretion remains to be fully elucidated. Here, we report that TMEM39, an ER-localized transmembrane protein, regulates production and secretory cargo trafficking of procollagen. We identify the C. elegans ortholog TMEM-39 from an unbiased RNAi screen and show that deficiency of tmem-39 leads to striking defects in cuticle collagen production and constitutively high ER stress response. RNAi knockdown of the tmem-39 ortholog in Drosophila causes similar defects in collagen secretion from fat body cells. The cytosolic domain of human TMEM39A binds to Sec23A, a vesicle coat protein that drives collagen secretion and vesicular trafficking. TMEM-39 regulation of collagen secretion is independent of ER stress response and autophagy. We propose that the roles of TMEM-39 in collagen secretion and ER homeostasis are likely evolutionarily conserved.