Immunoglobulin G (IgG) Fc fusion proteins of alpha(1)-acid glycoprotein (AGP), P-selectin glycoprotein ligand-1 (PSGL-1) or CD43 were used to probe the specificity KU-55933 of FucT-III-VII expressed alone in 293T and COS cells or together with O-glycan core enzymes in Chinese hamster ovary (CHO)-K1 cells. Western blotting with the monoclonal
antibodies CSLEX and KM93 showed that FucT-III and V-VII produced SLe(x) on core 2 in CHO cells. Only FucT-V, -VI and, with low activity, -VII worked on core 3 on CD43/IgG, but no SLe(x) was detected with CSLEX on PSGL-1/IgG with core 3. KM93 stained SLe(x) on core 2, but was not reactive with SLe(x) on core 3. FucT-III, V-VII made SLe(x) on N-glycans of AGP/IgG in CHO, but not in COS and 293T cells,
even though the same FucTs could make SLe(x) on CD43/IgG and PSGL-1/IgG in these cells. Our results define the specificities of FucT-III-VII in SLe(x) biosynthesis on O-glycans with different core structures and the fine specificity of the widely used anti-SLe(x) monoclonal antibody, KM93.”
“A detailed understanding of how the GH and IGF-I regulate muscle growth, especially in early vertebrates, LDC000067 Cell Cycle inhibitor is still lacking. The fine flounder is a flatfish species exhibiting remarkably slow growth, representing an intriguing model for elucidating growth regulatory mechanisms. Key components of the GH selleck kinase inhibitor system were examined in groups of fish
during periods of feeding, fasting, and refeeding. Under feeding conditions, there is an inherent systemic and local (muscle) GH resistance, characterized by higher levels of plasma GH than of IGF-I, skeletal muscle with a greater content of the truncated GH receptor (GHRt) than of full-length GHR (GHRfl), an impaired activation of the Janus kinase 2 (JAK2)-signal transducers and activators of transcription 5 (STAT5) signaling pathway, and low IGF-I expression. Fasting leads to further elevation of plasma GH levels concomitant with suppressed IGF-I levels. The ratio of GHRfl to GHRt in muscle decreases during fasting, causing an inactivation of the JAK2/STAT5 signaling pathway and suppressed IGF-I expression, further impairing growth. When fish are returned to nutritionally favorable conditions, plasma GH levels decrease, and the ratio of GHRfl to GHRt in muscle increases, triggering JAK2/STAT5 reactivation and local IGF-I expression, concomitant with increased growth. The study suggests that systemic IGF-I is supporting basal slow growth in this species, without ruling out that local IGF-I is participating in muscle growth. These results reveal for the first time a unique model of inherent GH resistance in the skeletal muscle of a nonmammalian species and contribute to novel insights of the endocrine and molecular basis of growth regulation in earlier vertebrates.