From Proteopediaproteopedia link
Crystal structure of Human PRL-1
[TP4A1_HUMAN] Protein tyrosine phosphatase which stimulates progression from G1 into S phase during mitosis. May play a role in the development and maintenance of differentiating epithelial tissues. Enhances cell proliferation, cell motility and invasive activity, and promotes cancer metastasis.  
Publication Abstract from PubMed
The PRL phosphatases, which constitute a subfamily of the protein tyrosine phosphatases (PTPs), are implicated in oncogenic and metastatic processes. Here, we report the crystal structure of human PRL-1 determined at 2.7A resolution. The crystal structure reveals the shallow active-site pocket with highly hydrophobic character. A structural comparison with the previously determined NMR structure of PRL-3 exhibits significant differences in the active-site region. In the PRL-1 structure, a sulfate ion is bound to the active-site, providing stabilizing interactions to maintain the canonically found active conformation of PTPs, whereas the NMR structure exhibits an open conformation of the active-site. We also found that PRL-1 forms a trimer in the crystal and the trimer exists in the membrane fraction of cells, suggesting the possible biological regulation of PRL-1 activity by oligomerization. The detailed structural information on the active enzyme conformation and regulation of PRL-1 provides the structural basis for the development of potential inhibitors of PRL enzymes.
Trimeric structure of PRL-1 phosphatase reveals an active enzyme conformation and regulation mechanisms.,Jeong DG, Kim SJ, Kim JH, Son JH, Park MR, Lim SM, Yoon TS, Ryu SE J Mol Biol. 2005 Jan 14;345(2):401-13. PMID:15571731
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.