Symplekin (SYMPK SPK)

Function

• heat-labile component of a multimolecular complex that functiond in histone mRNA 3'-end processing
• specific component of the tight junction (TJ) plaque
• might not be an exclusively junctional component
• may have a house-keeping rule
• may be required for pre-mRNA polyadenylation
• found in a heat-sensitive complex at least composed of several cleavage & polyadenylation specific & cleavage stimulation factors
• interacts with CPSF2, CPSF3 & CSTF2
• interacts with HSF1 in heat-stressed cells

Compartment

• cytoplasm, cytoskeleton
• cell junction, tight junction
• cell membrane; peripheral membrane protein, cytoplasmic side
• nucleus, nucleoplasm
• cytoplasmic face of adhesion plaques (major) & nucleoplasm (minor) (in cells with tight junction)
• nucleoplasm (in cells without tight junction)
• nuclear bodies of heat-stressed cells

Alternative splicing

• named isoforms=3
• additional isoforms seem to exist

Expression

• expressed in testis
• expressed in polar epithelia & Sertoli cells
• not expressed in vascular endothelia
• detected in stomach, duodenum, pancreas, liver, fetal brain, carcinomas, lens-forming cells, fibroblasts, lymphocytes, lymphoma cells, erythroleukemia cells (at the protein level)
• not found in endothelium of vessels, epidermis, intercalated disks, purkinje fiber cells of the heart & lymph node

Pathology

• may see use as a differentiation marker in the differential diagnosis of tumors

More general terms

• phosphoprotein

Component of

• tight junction

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=8189
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:8189
• OMIM: https://mirror.omim.org/entry/602388
• UniProt: http://www.uniprot.org/uniprot/Q92797.html