1GGW

CDC4P FROM SCHIZOSACCHAROMYCES POMBE

Summary for 1GGW

• Entry DOI: 10.2210/pdb1ggw/pdb
• Descriptor: PROTEIN (CDC4P) (1 entity in total)
• Functional Keywords: light chain, cytokinesis, cell cycle, ef-hand, cytokine
• Biological source: Schizosaccharomyces pombe (fission yeast)
• Cellular location: Cytoplasm: Q09196
• Total number of polymer chains: 1
• Total formula weight: 15543.48

Authors

Slupsky, C.M.,Hemmingsen, S.M.,McIntosh, L.P. (deposition date: 2000-09-25, release date: 2001-03-21, Last modification date: 2023-12-27)

Primary citation

Slupsky, C.M.,Desautels, M.,Huebert, T.,Zhao, R.,Hemmingsen, S.M.,McIntosh, L.P.
Structure of Cdc4p, a contractile ring protein essential for cytokinesis in Schizosaccharomyces pombe.
J.Biol.Chem., 276:5943-5951, 2001

PubMed Abstract: The Schizosaccharomyces pombe Cdc4 protein is required for the formation and function of the contractile ring, presumably acting as a myosin light chain. By using NMR spectroscopy, we demonstrate that purified Cdc4p is a monomeric protein with two structurally independent domains, each exhibiting a fold reminiscent of the EF-hand class of calcium-binding proteins. Although Cdc4p has one potentially functional calcium-binding site, it does not bind calcium in vitro. Three variants of Cdc4p containing single point mutations responsible for temperature-sensitive arrest of the cell cycle at cytokinesis (Gly-19 to Glu, Gly-82 to Asp, and Gly-107 to Ser) were also characterized by NMR and circular dichroism spectroscopy. In each case, the amino acid substitution only leads to small perturbations in the conformation of the protein. Furthermore, thermal unfolding studies indicate that, like wild-type Cdc4p, the three mutant forms are all extremely stable, remaining completely folded at temperatures significantly above those causing failure of cytokinesis in intact cells. Therefore, the altered phenotype must arise directly from a disruption of the function of Cdc4p rather than indirectly through a disruption of its overall structure. Several mutant alleles of Cdc4p also show interallelic complementation in diploid cells. This phenomenon can be explained if Cdcp4 has more than one essential function or, alternatively, if two mutant proteins assemble to form a functional complex. Based on the structure of Cdc4p, possible models for interallelic complementation including interactions with partner proteins and the formation of a myosin complex with Cdc4p fulfilling the role of both an essential and regulatory light chain are proposed.

PubMed: 11087750
DOI: 10.1074/jbc.M008716200

Experimental method

SOLUTION NMR