The first LIM domain of LIMK (LIM domain Kinase ): LIMK protein family is comprised of two members 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 depolymerisation. LIMKs can function in both cytoplasm and nucleus and are expressed in all tissues. Both LIMK1 and LIMK2 can act in the nucleus to suppress Rac/Cdc42-dependent cyclin D1 expression. However, LIMK1 and LIMk2 have different cellular locations. While LIMK1 localizes mainly at focal adhesions, LIMK2 is found in cytoplasmic punctae, suggesting that they may have different cellular functions. The LIM domains of LIMK 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.",