Copine A is essential for calcium homeostasis in Dictyostelium.

Copines are a family of calcium-dependent phospholipid-binding proteins found in most eukaryotic organisms. The expression of multiple copine genes is dysregulated in various types of human cancers. Yet, a common mechanistic function for copines remains enigmatic.

Secreted Frizzled-Related Protein 1a regulates hematopoietic development in a dose-dependent manner.

Hematopoietic stem and progenitor cells (HSPCs) arise only during embryonic development, and their identity specification, emergence from the floor of the dorsal aorta, and proliferation are all tightly regulated by molecular mechanisms such as signaling cues. Among these, Wnt signaling plays an important role in HSPC specification, differentiation, and self-renewal, requiring precise modulation for proper development and homeostasis. Wnt signaling is initiated when a Wnt ligand binds to cell surface receptors such as those encoded by the gene family, activating intracellular signaling pathways that regulate gene expression.

WNT9A and WNT9B in Development and Disease.

WNT9 paralogues, WNT9A and WNT9B, are secreted ligands driving both the canonical (β-catenin dependent) and non-canonical (β-catenin independent) Wnt signaling pathways. These pathways play roles in cell fate determination, embryonic patterning, bone development, and organogenesis, among other biological processes. Studies of Wnt9a and Wnt9b mutant animals demonstrate that they have specific and overlapping roles in these processes.

The E3 Ubiquitin Ligase Trip12 attenuates Wnt9a/Fzd9b signaling during hematopoietic stem cell development.

Wnt signaling is essential for both the development and homeostasis of diverse cellular lineages, including hematopoietic stem cells. Organism-wide, Wnt signals are tightly regulated, as overactivation of the pathway can lead to tumorigenesis. Although numerous Wnt ligands and Frizzled (Fzd) receptors exist, how particular Wnt/Fzd pairings are established and how their signals are regulated is poorly understood.

Copine C plays a role in adhesion and streaming in .

Copines are a family of calcium-dependent membrane-binding proteins. To study these proteins, anull mutant for was created in , which has six copines genes (). During development, cells were able to aggregate, but did not form streams.

Phosphatidylserine exposure promotes increased adhesion in Dictyostelium Copine A mutants.

The phospholipid phosphatidylserine (PS) is a key signaling molecule and binding partner for many intracellular proteins. PS is normally found on the inner surface of the cell membrane, but PS can be flipped to the outer surface in a process called PS exposure. PS exposure is important in many cell functions, yet the mechanisms that control PS exposure have not been extensively studied.

Copine A regulates the size and exocytosis of contractile vacuoles and postlysosomes in Dictyostelium.

Copines are a family of cytosolic proteins that associate with membranes in a calcium-dependent manner and are found in many eukaryotic organisms. Dictyostelium discoideum has six copine genes (cpnA-cpnF), and cells lacking cpnA(cpnA ) have defects in cytokinesis, chemotaxis, adhesion, and development. CpnA has also been shown to associate with the plasma membrane, contractile vacuoles (CV), and organelles of the endolysosomal pathway.