Isoforms of the Cytoskeletal LIM-Domain Protein Zyxin in the Early Embryogenesis of Xenopus laevis

Abstract Objective: The study of highly conserved mechanosensitive proteins, such as zyxin, is essential due to their role in shaping embryos of all animals during embryogenesis through coordinated morphogenetic processes and controlled cell differentiation. This study aims to identify endogenous zyxin isoforms in Xenopus laevis and investigate changes in their abundance and intracellular localization during embryogenesis. Methods: Endogenous proteins were primarily detected using specific antibodies. Polyclonal antibodies targeting the C-terminal region of zyxin containing the NES and three LIM domains (438–663 aa), as well as antibodies against the N-terminal proline-rich region of Zyxin (1–373 aa) crucial for interactions with actinin and cytoskeletal proteins, were employed. Western blotting with these antibodies was conducted on Xenopus laevis embryo cell samples after fractionation into nuclear and cytoplasmic fractions. Results and Discussion: The study revealed multiple isoforms of zyxin in Xenopus laevis , including a full-length modified protein (105 kDa), an unmodified form (70 kDa), and two truncated forms of 45 and 37 kDa. The number and subcellular distribution of the truncated forms were found to vary based on the developmental stage, with increased levels of the 45 and 37 kDa isoforms observed in the early stages. Conclusions: This work provides novel insights into changes in the abundance and localization of zyxin isoforms during embryonic development, shedding light on the dynamics of this mechanosensitive protein in the embryo.