Our previous studies have shown that α-Tocopherol-associated protein (TAP), a vitamin E binding protein, may function as a tumor suppressor-like factor in breast carcinogenesis.
We further suggest that this RNA-binding protein may function to translationally-regulate or interact with key factors required to guide the germ cells through development, from stage to stage, and is required for the post-migratory pluripotent germ cells to begin reprogramming and switch from mitotic to meiotic divisions (Figure 9A 9D).
Conserved residues in alignments of NifH-like sequences with NifH sequences show that 4Fe-4S iron sulfur cluster-ligating cysteines and the P-loop/MgATP binding motif are invariant, suggesting that these proteins may function analogously to dinitrogenase reductase.
These proteins may function as chaperones, altering or maintaining specific RNA structures that permit binding of the translational machinery (for review see [10]).
These binding proteins may perform functions extracellularly (e.g. in plasma) or transport these agents; to the nucleus to interact with nuclear receptors (principally PPARs and retinoic acid receptors 16) or for interaction with metabolic enzymes.
Plastidic mRNA binding proteins often function in association with other proteins; in fact, the rbcL mRNA-based affinity purification of several proteins along with RLSB provides evidence that this protein may function as part of a larger protein complex.
Because Cl-, Na+, K+ and Ca2+ channels were implicated to modulate sperm function [ 37- 41], ion binding proteins may play crucial roles in post-translational regulation in sperm.
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].
