SMART accession number:SM00392
Description: Binds actin monomers, membrane polyphosphoinositides and poly-L-proline.
Interpro abstract (IPR005455):

This entry represents the Profilin family, which are small eukaryotic proteins that have different functions. In plants, they are major allergens present in pollens [(PUBMED:21458043)].

The majority of the Profilin family members binds to monomeric actin (G-actin) in a 1:1 ratio thus preventing the polymerisation of actin into filaments (F-actin). They can also in certain circumstance promote actin polymerisation [(PUBMED:16542844)]. However, some Profilin family members, such as Profilin4 from mammals, does not binds to actin and may have functions distinct from regulating actin dynamics [(PUBMED:19419568)]. It plays a role in the assembly of branched actin filament networks, by activating WASP via binding to WASP's proline rich domain [(PUBMED:11137023)]. Profilin may link the cytoskeleton with major signalling pathways by interacting with components of the phosphatidylinositol cycle and Ras pathway [(PUBMED:7945274),(PUBMED:1651167)].

Some Profilins can also bind to polyphosphoinositides such as PIP2 [(PUBMED:11034907)]. Overall sequence similarity among profilin from organisms which belong to different phyla (ranging from fungi to mammals) is low, but the N-terminal region is relatively well conserved. The N-terminal region is thought to be involved in actin binding.

Family alignment:
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There are 1685 PROF domains in 1683 proteins in SMART's nrdb database.

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