Functional analysis of a novel intracellular calcium-binding protein peflin

点击翻译按钮获取中文摘要

Peflin is a new member of the penta-EF-hand (PEF) calcium-binding protein family that includes ALG-2 (apoptosis linked gene 2), calpain, and sorcin. We prepared a specific monoclonal antibody that recognized peflin. By immunoprecipitation followed by Western blot analysis, peflin and ALG-2 have been found to form a heterodimer that dissociates in a calcium-dependent manner. While peflin is localized to cytoplasm, ALG-2 is localized in both cytoplasm and nuclei. Peflin may regulate function of ALG-2 by heterodimerization. We identified PEF proteins in the cellular slime mold Dictyostelium discoideum, a model organism that displays transformation from unicellular form to multicellular form during its life cycle. Phylogenetic analysis has revealed that ALG-2 and/or peflin are conserved and present ubiquitously in higher and lower eukaryotes while calpain and sorcin are rather new in evolution. By the yeast two-hybrid screening, ALG-2, peflin, Alix and annexin XI were isolated as ALG-2-interacting proteins. The N-terminal Gly/Tyr/Pro-rich region of annexin has a sequence similar to that of the C-terminal region of Alix, suggesting presence of a common binding motif in these regions