In vivo the activity of IGF is regulated by the IGF-binding proteins, which function to either enhance or inhibit the mitogenic activities of IGF1 (Jones and Clemmons, 1995).
FBPs have different functions based on their biochemical properties and can be divided into 3 classes: high-affinity folate binding proteins (HFBP), membrane-associated folate-binding proteins, which function in the transport of folate compounds across cell membranes, and cytoplasmic-binding proteins with a high affinity for specific reduced-folate compounds [ 5].
We previously showed that LARK is a Drosophila RNA-binding protein which functions downstream of the clock to mediate behavioral outputs.
MetJ is a homodimeric DNA-binding protein which functions in complex with two molecules of the co-repressor, SAM.
TLE1 is an ES cell-specific gene coding a RNA-binding protein which functions downstream of the LIF and Oct3/4 pathways [ 32, 33].
EPLIN is an actin-binding protein, which functions to bundle actin filaments; therefore, EPLIN presence is required at AJ along with filamentous actin.
These proteins are transported by the cytosolic adaptor p62/SQSTM1 and various ubiquitin receptor proteins, which function as ubiquitin-binding scaffold proteins, binding aggregates in the cytosol (Elsasser and Finley, 2005).
The cognate ligand for CD40, CD154 (CD40 ligand, CD40L, gp39, TRAP) does not bind other TNFR although it can interact with the soluble complement inhibitor C4b binding protein which may function as a competitive inhibitor of CD40 activation [8].
Hepatic GK is regulated at a post-translational level through binding to GKRP (GK regulatory protein), which functions as an anchor protein, modulating GK activity and mediating its nuclear translocation (Vandercammen and Van Schaftingen, 1990 , 1991.
The D3-phosphorylated products further act as membrane tethers to several phospholipid binding proteins which regulate a diverse range of cell functions, including proliferation, cell survival, degranulation, vesicular trafficking, and cell migration [ 1].
