Catalytic and Non-catalytic Functions of Testis Specific Lactate Dehydrogenase

摘要

Preliminary evidence has been obtained that suggests LDH-C_4 has non-catalytic functions that involve protein-protein and protein-nucleic acid interactions. We are identifying these macromolecular interactions in order to dissect the sites required for these associations and mechanisms for protein stability. We present evidence here that LDH-C_4 is tightly bound to the fibrous sheath of the sperm flagellum. AKAP null spermatozoa contain LDH-C_4 only in the soluble fraction compared to partitioning of this isozyme in cytoplasm and fibrous sheath of wild-type sperm. We are investigating whether LDH-C_4 association with the fibrous sheath is direct or via an AKAP tether. Additionally, we describe here LDH-C_4-mRNA interaction.