The second LIM domain of LIMK1 (LIM domain Kinase 1)
The second LIM domain of LIMK1 (LIM domain Kinase 1): LIMK1 belongs to the LIMK protein family, which comprises LIMK1 and LIMK2. LIMK contains two LIM domains, a PDZ domain, and a kinase domain. LIMK is involved in the regulation of actin polymerization and microtubule disassembly. LIMK influences architecture of the actin cytoskeleton by regulating the activity of the cofilin family proteins cofilin1, cofilin2, and destrin. The mechanism of the activation is to phosphorylates cofilin on serine 3 and inactivates its actin-severing activity, and altering the rate of actin depolymerization. LIMKs can function in both cytoplasm and nucleus. Both LIMK1 and LIMK2 can act in the nucleus to suppress Rac/Cdc42-dependent cyclin D1 expression. LIMK1 is expressed in all tissues and is localized to focal adhesions in the cell. LIMK1 can form homodimers upon binding of HSP90 and is activated by Rho effector Rho kinase and MAPKAPK2. LIMK1 is important for normal central nervous system development, and its deletion has been implicated in the development of the human genetic disorder Williams syndrome. Moreover, LIMK1 up-regulates the promoter activity of urokinase type plasminogen activator and induces its mRNA and protein expression in breast cancer cells. The LIM domains have been shown to play an important role in regulating kinase activity and likely also contribute to LIMK function by acting as sites of protein-to-protein interactions. All LIM domains are 50-60 amino acids in size and share two characteristic zinc finger motifs. The two zinc fingers contain eight conserved residues, mostly cysteines and histidines, which coordinately bond to two zinc atoms. LIM domains function as adaptors or scaffolds to support the assembly of multimeric protein complexes.
Comment:The two zinc fingers contain eight conserved residues, mostly cysteines and histidines, which coordinately bond to two zinc atoms. The Zn binding residues of LIM domain are highly conserved.
Jiyao W et al.(2023). "The conserved domain database in 2023.",