High impact information on LAP2

• We show that TPX2 interacts with lamina-associated polypeptide 2 (LAP2), a protein known to be required for nuclear assembly in interphase extracts and in vitro [1].
• LAP2 belongs to a family of nuclear membrane proteins sharing a 43 residue LEM domain [2].
• Roles of LAP2 proteins in nuclear assembly and DNA replication: truncated LAP2beta proteins alter lamina assembly, envelope formation, nuclear size, and DNA replication efficiency in Xenopus laevis extracts [3].
• The lamina-associated polypeptide 2 (LAP2) isoforms beta, gamma and omega of zebrafish: developmental expression and behavior during the cell cycle [4].
• In counterpart oocytes, eggs, and embryos contained one LAP2-related integral membrane proteins of Mr 84,000 [5].

Biological context of LAP2

• The LAP2/TP protein of Mr 84,000 is present in the early embryos but its amount decreases during embryogenesis concomitant with the increase of XLAP2 in the embryo [5].
• Lamina-associated polypeptide 2beta (LAP2beta) of vertebrates is an integral membrane protein of the inner nuclear membrane that is generated by alternative splicing from the LAP2 gene [6].
• GFP-LAP2beta fusion proteins of Xenopus, zebrafish, and rat that contained this sequence do compete with endogenous LAP2 in transfected cells for the same binding sites in the lamina [6].

Anatomical context of LAP2

• In the majority of Xenopus somatic cells including cultured kidney epithelial cells (A6 cells) there is only one major LAP2 isoform expressed that has the highest similarities with the mammalian LAP2beta whereas isoforms corresponding in size to the mammalian LAP2gamma and alpha are not detectable [6].

Analytical, diagnostic and therapeutic context of LAP2

• Northern blot analysis with the XLAP2 cDNA showed that a single hybridizing mRNA band of 1.8-2.0 kb was present in Xenopus somatic cells whereas two other hybridizing mRNA species of 2.8-3.0 and 0 [5].

References