Concentration of singly phosphorylated myosin II regulatory light chain along the cleavage furrow of dividing HeLa cells

摘要

We developed a polyclonal antibody P1 which recognizes regulatory light chain of myosin II (MRLC) phosphorylated by Ca2+/calmodulin-dependent myosin light chain kinase (MLCK). The antibody P1 was produced against a synthetic, singly phosphorylated peptide, Lys-Arg-Pro-Gln-Arg-Ala-Thr-phospho Ser-Asn-Val-Phe (residues 13-23 on MRLC from chicken gizzard). The phosphorylation of this serine residue (MLCK site) on the intact MRLC induces activation of myosin ATPase activity in vitro. Immunoblotting studies showed that the antibody P1 specifically recognizes singly phosphorylated MRLC. Immunofluorescence studies demonstrated that the singly phosphorylated MRLC was localized mainly around the chromosomes in metaphase cells and was later concentrated along the cleavage furrow during cytokinesis. The result suggests that phosphorylation of MRLC plays an important role in the cleavage furrow during cytokinesis. [References: 18]