The Nesprin-1/-2 ortholog ANC-1 regulates organelle positioning in C. elegans independently from its KASH or actin-binding domains

KASH proteins in the outer nuclear membrane comprise the cytoplasmic half of LINC complexes that connect nuclei to the cytoskeleton. Caenorhabditis elegans ANC-1, an ortholog of Nesprin-1/2, contains actin-binding and KASH domains at opposite ends of a long spectrin-like region. Deletion of either the KASH or calponin homology (CH) domains does not completely disrupt nuclear positioning, suggesting neither KASH nor CH domains are essential. Deletions in the spectrin-like region of ANC-1 led to significant defects, but only recapitulated the null phenotype in combination with mutations in the trans-membrane span. In anc-1 mutants, the ER, mitochondria, and lipid droplets were unanchored, moving throughout the cytoplasm. The data presented here support a cytoplasmic integrity model where ANC-1 localizes to the ER membrane and extends into the cytoplasm to position nuclei, ER, mitochondria, and likely other organelles in place.

P-Null Phenotype Due to a Rare Frame-Shift Mutation and with Allo-Anti-PP1Pk Causing a Severe Hemolytic Transfusion Reaction: A Case Report with Clinical Management

Introduction:The identification of alloantibodies to high-frequency antigens (HFA) and subsequent transfusion management can be challenging and often poses a problem in finding the compatible blood for transfusion. The aim of this study was to investigate the specificity of the antibody to the HFA causing a hemolytic transfusion reaction (HTR) and procure the compatible blood unit for future transfusion. Case presentation:A 4-year-old female met with a head injury that led to intracranial bleeding and surgical intervention was required to remove blood clots. In the face of anemia, blood transfusion was planned. The pretransfusion tests on her blood sample revealed the presence of a pan-reactive alloantibody with hemolytic properties. She was transfused with 10 mL of the least incompatible red blood cells (RBCs) to which she reacted with signs of clinical hemolysis, i.e., chill, rigor, fever, and hemoglobinuria, on 3 different occasions. Despite her anemia, she was managed by medical intervention only. Her antibody reacted with all RBCs tested, except autologous and P-null (p phenotype) cells. Her RBCs did not react with anti-PP1Pk, which corroborated her phenotype as P-null. The genomic study revealed she was hemi- or homozygous or for a deletion of 26-bp in A4GALTexon 3, previously reported as causing the P-null phenotype and designated A4GALT*01N.019.Conclusion:This report documents a rare case of the P-null phenotype with an alloanti-PP1Pk causing a severe HTR to transfusion of the trial dose of the least incompatible blood. The case is the first example of this specific A4GALTmutation found in India.

The Nesprin-1/-2 ortholog ANC-1 regulates organelle positioning in C. elegans without its KASH or actin-binding domains

KASH proteins in the outer nuclear membrane comprise the cytoplasmic half of LINC complexes that connect nuclei to the cytoskeleton. Caenorhabditis elegans ANC-1, an ortholog of Nesprin-1/2, contains actin-binding and KASH domains at opposite ends of a long spectrin-like region. Deletion of either the KASH or calponin homology (CH) domains does not completely disrupt nuclear positioning, suggesting neither KASH nor CH domains are essential. Deletions in the spectrin-like region of ANC-1 led to significant defects, but only recapitulated the null phenotype in combination with mutations in the trans-membrane span. In anc-1 mutants, the ER was unanchored, moving throughout the cytoplasm, and often fragmented. The data presented here support a cytoplasmic integrity model where ANC-1 localizes to the ER membrane and extends into the cytoplasm to position nuclei, ER, mitochondria, and likely other organelles in place.