[10] PAK1 regulates cytoskeleton remodeling, phenotypic signaling and gene expression, and affects a wide variety of cellular processes such as directional motility, invasion, metastasis, growth, cell cycle progression, angiogenesis.

Examples of PAK1-regulated cellular processes include dynamic of actin and microtubule fibers, critical steps during cell cycle progression, motility and invasion, redox and energy metabolism, cell survival, angiogenesis, DNA-repair, hormone sensitivity, and gene expression.

Functional implications of the PAK1 signaling are exemplified by its role in oncogenesis,[9] viral pathogenesis,[15][16] cardiovascular dysregulation,[17] and neurological disorders.

[19] Reversible covalent binding of IPA-3 to the PAK1 regulatory domain prevents GTPase docking and the subsequent switch to a catalytically active state.

However, IPA-3's pharmacokinetic properties as well as undesirable redox effects in cells, due to the continuous reduction of the sulfhydryl moiety, make it unsuitable for clinical development.

[20] PAK1 activity is stimulated by a large number of upstream activators and signals, ranging from EGF,[21] heregulin-beta 1,[22] VEGF,[23] basic fibroblast growth factor,[24] platelet-derived growth factor,[25] estrogen,[26] lysophosphatidic acid,[27] phosphoinositides,[28] ETK,[29] AKT,[30] JAK2,[31] ERK,[32] casein kinase II,[33] Rac3,[34] chemokine (C-X-C motif) ligand 1,[35] breast cancer anti-estrogen resistance 3,[36] Kaposi's sarcoma-associated herpesvirus-G protein-coupled receptor,[37] hepatitis B virus X protein,[38] STE20-related kinase adaptor protein α,[39] RhoI,[40] Klotho,[41] N-acetylglucosaminyl transferase V,[42] B-Raf proto-oncogene,[43] casein kinase 2-interacting protein 1,[44] and filamin A.

[45] Functions of PAK1 are regulated by its ability to phosphorylate downstream effector substrates, scaffold activity, redistribution to distinct sub-cellular cellular sub-domains, stimulation or repression of expression of its genomic targets either directly or indirectly, or by all of these mechanisms.