Association of cell cycle protein kinases with the cytoskeleton of cultured myoblasts /

Abstract

These studies investigated the role of the protein kinase cdk1 (cdc2) with regard to the cytoskeleton of cultured C2C12 skeletal muscle myoblasts. The cyclin-dependent protein kinases (cdks) are involved in regulating entry into and progression through various stages of the cell cycle. The cell cycle consists of four precise phases that dividing cells pass through: M, G1, S, and G2 phase. Cdc2, a member of the cdk family, is known for its role in facilitating the transition state from G2 to M phase. In order to examine the possibility that cdc2 is involved in cytokinesis two factors must be addressed. First, synchronization of C2C12 cells is critical to ensure that all cells are in the same phase of M phase before extraction of the cytoskeleton can occur. Establishing the presence of cdc2 during mitosis leads to the examination of its location and with what it is specifically linked to. Secondly, the removal of actin, a cytoskeletal protein, as well as nucleic acids is essential to determine the connection between cdc2 and actin or cdc2 and chromatin. This is important because actin and myosin are key components of the contractile ring that aids in the process of cytokinesis. If cdc2 is associated with actin, then cdc2 can possibly playa role in cytokinesis. After synchronization of C2C12 cells at mitosis, the cytoskeleton was isolated using detergent extraction protocols. Protein composition was analyzed by Western Blot to investigate the presence of cdc2 in the cytoskeleton fractions with and without actin and chromatin. Ultimately, the aim of this study was to show that cdc2 plays a part in cytokinesis by proving that cdc2 is linked to the cytoskeletal protein actin.