Liprin-beta-1 is a member of the LAR (leukocyte common antigen-related) protein tyrosine phosphatase-interacting protein (liprin) family []. Liprin-beta-1 interacts with metastasis-associated protein S100A4 (Mts1), and this interaction results in the inhibition of liprin-beta-1 phosphorylation by protein kinase C and protein kinase CK2 in vitro []. In Xenopus, it plays a role in the maintenance of lymphatic vessel integrity [].Liprin was originally identified as binding partners of the receptor protein tyrosine phosphatase LAR (leukocyte common antigen-related), which functions in axon guidance and mammary gland development []. In vertebrates, there are two families of liprins, liprin-alpha and liprin-beta, which have four (alpha1-4) and two (beta1-2) members. Liprins contain an N-terminal coiled-coil domain and a C-terminal liprin homology (LH) region comprised of three sterile alpha motif (SAM) domains. The N-terminal coiled coils of liprin-alpha act as binding regions for several synaptic protein, while the SAM repeats can bind to both phosphatases and protein kinases []. The autophosphorylation of liprin regulates its association with LAR []. Interestingly, all Liprin-alpha genes are subject to alternative splicing, which is regulated in a developmental manner []. The structure of the humanCASK/liprin-alpha/liprin-beta ternary complex has been revealed [].
