Preferred Label : Actin Branching Pathway;
NCIt related terms : Y branching of actin filaments;
Alternative definition : BIOCARTA: Mammalian cell motility requires actin polymerization in the direction of
movement to change membrane shape and extend cytoplasm into lamellipodia. The polymerization
of actin to drive cell movement also involves branching of actin filaments into a
network oriented with the growing ends of the fibers near the cell membrane. Manipulation
of this process helps bacteria like Salmonella gain entry into cells they infect.
Two of the proteins involved in the formation of Y branches and in cell motility are
Arp2 and Arp3, both members of a large multiprotein complex containing several other
polypeptides as well. The Arp2/3 complex is localized at the Y branch junction and
induces actin polymerization. Activity of this complex is regulated by multiple different
cell surface receptor signaling systems, activating WASP, and Arp2/3 in turn to cause
changes in cell shape and cell motility. Wasp and its cousin Wave-1 interact with
the Arp2/3 complex through the p21 component of the complex. The crystal structure
of the Arp2/3 complex has revealed further insights into the nature of how the complex
works. Activation by Wave-1, another member of the WASP family, also induces actin
alterations in response to Rac1 signals upstream. Wave-1 is held in an inactive complex
in the cytosol that is activated to allow Wave-1 to associate with Arp2/3. While WASP
is activated by interaction with Cdc42, Wave-1, is activated by interaction with Rac1
and Nck. Wave-1 activation by Rac1 and Nck releases Wave-1 with Hspc300 to activate
actin Y branching and polymerization by Arp2/3. Different members of this gene family
may produce different actin cytoskeletal architectures. The immunological defects
associated with mutation of the WASP gene, the Wiskott-Aldrich syndrome for which
WASP was named, indicates the importance of this system for normal cellular function.
(This definition may be outdated - see the DesignNote.);
NCIt note : The BIOCARTA Definition (ALT_DEFINITION) for this pathway concept was provided by
BioCarta. This property was not created by, nor is it maintained by the NCI Thesaurus
staff. Additionally, BioCarta is no longer updating its pathway data; thus, the BIOCARTA
Definition might be outdated or inaccurate. Please see the Terms and Conditions for
Use at http://www.biocarta.com/.;
Biocarta ID : h_actinYPathway;
Origin ID : C38973;
UMLS CUI : C1515875;
Semantic type(s)
- has_gene_product_element
- pathway_has_gene_element
