Identification and Validation of Putative Nesprin Variants

Abstract

SummaryNesprins are a family of multi-isomeric scaffolding proteins that were originally identified at the nuclear envelope (NE), where they bind to lamin A/C, emerin and SUN-domain containing proteins, to form the LInker of Nucleoskeleton-andCytoskeleton (LINC) complex that connects the NE to the actin cytoskeleton. However, nesprin genes also give rise to a variety of tissue specific variants of different sizes with potential roles beyond the NE. These variants are generated through alternative initiation, termination and splicing, which makes nesprin biology very complex to study due to the difficulty in generating specific antibodies and/or short interfering RNAs (siRNA) to particular isoforms. In order to distinguish genuine nesprin variants and eliminate confusion with degradation products of larger nesprin isoforms, in this chapter we discuss methods including 5' and 3' Rapid Amplification of cDNA Ends (RACE) and RT-PCR in combination with EST database searching, for identifying and validating putative nesprin isoforms. This information is essential to allow a better understanding of nesprin functions in different cell types.

Autoantibodies against HSF1 and CCDC155 as Biomarkers of Early-Stage, High-Grade Serous Ovarian Cancer

“…We also identified coiled-coil domain containing 155 (CCDC155; KASH5; Nesprin-5) as a potential cancer-associated autoantigen. CCDC155 is a member of the Klarsicht, ANC-1, and Syne Homology (KASH) family of mammalian dynein-binding proteins, that participate in mechanical connections between the nuclear envelope and actin cytoskeleton (43)(44)(45). KASH proteins play important roles in nuclear migration and positioning during cell cycle, signal transduction, and DNA repair and in the regulation of invadopodia function in tumor cells in vitro (46,47).…”

“…As part of the SUN1 LINC complex, CCDC155 controls the progression of meiosis in germ cells; CCDC155-deficient mice (both male and female) exhibit meiotic arrest, spindle abnormalities, and defects in homologous chromosome pairing (44,45). CCDC155 also exhibits haplotype-dependent, allele-specific methylation (48), which is tissue-type specific; notably, several other nesprins can be found as tissue-specific variants (43). The recognition of CCDC155 as a cancer-associated antigen could therefore arise as a consequence of epigenetic changes occurring in ovarian cancer cells (49).…”