Identification of a polyphosphoinositide-binding sequence in an actin monomer-binding domain of gelsolin.

The interaction of the cell-contact proteins VASP and vinculin is regulated by phosphatidylinositol-4,5-bisphosphate

“…It is conceivable that F-actin binding is due, at least in part, to the electrostatic attraction of the negative charges exposed on the surface of the actin filaments with the positively charged surface of these helices, although no prediction can be made as to which aminoacid residues within these regions might be involved in PIP 2 binding. We did not find any motif corresponding to the specific consensus sequence of basic amino acids identified in some PIP 2 -binding proteins of the microfilament system, such as gelsolin and cofilin [38].…”

Phosphatidylinositol polyphosphate binding to the mammalian septin H5 is modulated by GTP

“…As shown in Figure 3c, PtdIns(4,5)P 2 bound to all of the truncation mutants except ∆112, indicating that the binding site must reside between amino acids 112 and 230. Within these 118 residues lies a highly basic sequence between amino acids 135 and 141 that is very similar to polybasic sequences found in gelsolin and in members of the GRK4/5/6 family [26,29]. Related poly-basic sequences are found at the same location in septins from Drosophila and yeast, and in almost all of the mammalian septins (Figure 4a) [2].…”

“…Nevertheless, PtdInsP 2 binding has also been demonstrated in many proteins lacking PH domains, suggesting that other protein motifs might also confer this property. A deletion analysis of gelsolin was the first to demonstrate that PtdInsP 2 can bind to sequences rich in basic amino acids, and that this binding is specific [25][26][27][28][29][30]. Like many other highly charged proteins, H5 contains a number of motifs that have a polybasic nature similar to the PtdInsP 2 -binding site found in gelsolin.…”

“…Here, we have shown that this motif is capable of specific interactions with PtdInsP 2 . Polybasic PtdInsP 2binding sites were first identified in the actin-severing protein gelsolin [26] and later in a variety of proteins, including profilin [27,30], G-protein-coupled receptor kinases [29], inward rectifying potassium channels and Na + -Ca 2+ exchangers [28]. In general, these sequences are rich in lysine and arginine, and bind PtdInsP 2 with a lower affinity than has been observed for PH domains.…”

Coordinated activity of amoebic formin and profilin are essential for phagocytosis

“…Acanthamoeba profilin‐II isoform has the highest affinity for PI(4,5)P 2 . Similarly, human profilin‐I has more basic amino acid thus it interacts comparatively better with PI(4,5)P 2 than profilin‐II (Lambrechts et al., 1997; Yu et al., 1992). In vitro studies using micelles and vesicles showed binding of profilin with PI(4,5)P 2 disrupt the interaction between profilin–actin complex by same mechanism as ATP–actin monomers are released.…”