Microarray data on altered transcriptional program of Phgdh-deficient mouse embryonic fibroblasts caused by ʟ-serine depletion

Inherent ʟ-Ser deficiency culminates in intrauterine growth retardation, severe malformation of multiple organs particularly the central nervous system, and perinatal or early postnatal death in human and mouse. To uncover the molecular mechanisms underlying the growth-arrested phenotypes of l-Ser deficiency, we compared gene expression profiles of mouse embryonic fibroblasts deficient in 3-phosphoglycerate dehydrogenase (Phgdh), the first enzyme of de novo ʟ-Ser synthetic pathway, between ʟ-Ser-depleted and -supplemented conditions. The datasets (CEL and CHP files) from this study are publicly available on the Gene Expression Omnibus repository (accession number GEO: GSE55687). Keywords: Serine, PHGDH, Microarray, Inborn error, Neu-Laxova syndrom

Identification of a Novel Protein MICS1 that is Involved in Maintenance of Mitochondrial Morphology and Apoptotic Release of Cytochrome c

Mitochondrial morphology dynamically changes in a balance of membrane fusion and fission in response to the environment, cell cycle, and apoptotic stimuli. Here, we report that a novel mitochondrial protein, MICS1, is involved in mitochondrial morphology in specific cristae structures and the apoptotic release of cytochrome c from the mitochondria. MICS1 is an inner membrane protein with a cleavable presequence and multiple transmembrane segments and belongs to the Bi-1 super family. MICS1 down-regulation causes mitochondrial fragmentation and cristae disorganization and stimulates the release of proapoptotic proteins. Expression of the anti-apoptotic protein Bcl-XL does not prevent morphological changes of mitochondria caused by MICS1 down-regulation, indicating that MICS1 plays a role in maintaining mitochondrial morphology separately from the function in apoptotic pathways. MICS1 overproduction induces mitochondrial aggregation and partially inhibits cytochrome c release during apoptosis, regardless of the occurrence of Bax targeting. MICS1 is cross-linked to cytochrome c without disrupting membrane integrity. Thus, MICS1 facilitates the tight association of cytochrome c with the inner membrane. Furthermore, under low-serum condition, the delay in apoptotic release of cytochrome c correlates with MICS1 up-regulation without significant changes in mitochondrial morphology, suggesting that MICS1 individually functions in mitochondrial morphology and cytochrome c release