Integrin beta-1 can exist as different isoforms via alternative splicing. Six alternatively spliced variants have been found for this gene which encode five proteins with alternate C-termini.[6] Integrin receptors exist as heterodimers, and greater than 20 different integrin heterodimeric receptors have been described. All integrins, alpha and beta forms, have large extracellular and short intracellular domains.[7] The cytoplasmic domain of integrin beta-1 binds to the actincytoskeleton.[8] Integrin beta-1 is the most abundant beta-integrin expressed and associates with at least 10 different integrin-alpha subunits.[7]
Three novel isoforms of integrin beta-1 have been identified, termed beta-1B, beta-1C and beta-1D. Integrin beta-1B is transcribed when the proximal 26 amino acids of the cytoplasmic domain in exon 6 are retained and then succeeded by a 12 amino acid stretch from an adjacent intronic region.[14] The integrin beta-1B isoform appears to act as a dominant negative in that it inhibits cell adhesion.[15] A second integrin beta-1 isoform, termed beta-1C, was described to have an additional 48 amino acids appended to the 26 amino acids in the cytoplasmic domain;[16] the function of this isoform was an inhibitory one on DNA synthesis in the G1 phase of the cell cycle.[17] The third isoform, termed beta-1D, is a striated muscle-specific isoform, which replaces the canonical beta-1A isoform in cardiac and skeletal muscle cells. This isoform is produced from splicing into a novel additional exon between exons 6 and 7. The cytoplasmic domain of integrin beta-1D replaces the distal 21 amino acids (present in integrin beta-1A) with an alternative stretch of 24 amino acids (13 unique).[18][19]
In patients with sensitive-motor polyneuropathy, levels of integrin alpha-7B, integrin beta-1D and agrin were significantly reduced nearly to undetectable levels; and this corresponded with lower mRNA levels.[22]
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Goodfellow PJ, Nevanlinna HA, Gorman P, Sheer D, Lam G, Goodfellow PN (Jan 1989). "Assignment of the gene encoding the beta-subunit of the human fibronectin receptor (beta-FNR) to chromosome 10p11.2". Annals of Human Genetics. 53 (Pt 1): 15–22. doi:10.1111/j.1469-1809.1989.tb01118.x. PMID2524991. S2CID36485270.
^Meredith J, Takada Y, Fornaro M, Languino LR, Schwartz MA (Sep 1995). "Inhibition of cell cycle progression by the alternatively spliced integrin beta 1C". Science. 269 (5230): 1570–2. Bibcode:1995Sci...269.1570M. doi:10.1126/science.7545312. PMID7545312.
^Zhidkova NI, Belkin AM, Mayne R (Sep 1995). "Novel isoform of beta 1 integrin expressed in skeletal and cardiac muscle". Biochemical and Biophysical Research Communications. 214 (1): 279–85. doi:10.1006/bbrc.1995.2285. PMID7545396.
^Anastasi G, Cutroneo G, Trimarchi F, Santoro G, Bruschetta D, Bramanti P, Pisani A, Favaloro A (Dec 2004). "Evaluation of sarcoglycans, vinculin-talin-integrin system and filamin2 in alpha- and gamma-sarcoglycanopathy: an immunohistochemical study". International Journal of Molecular Medicine. 14 (6): 989–99. doi:10.3892/ijmm.14.6.989. PMID15547664.
^Radford KJ, Thorne RF, Hersey P (May 1996). "CD63 associates with transmembrane 4 superfamily members, CD9 and CD81, and with beta 1 integrins in human melanoma". Biochemical and Biophysical Research Communications. 222 (1): 13–8. doi:10.1006/bbrc.1996.0690. PMID8630057.
^ abMazzocca A, Carloni V, Sciammetta S, Cordella C, Pantaleo P, Caldini A, Gentilini P, Pinzani M (Sep 2002). "Expression of transmembrane 4 superfamily (TM4SF) proteins and their role in hepatic stellate cell motility and wound healing migration". Journal of Hepatology. 37 (3): 322–30. doi:10.1016/S0168-8278(02)00175-7. PMID12175627.
^Hadari YR, Arbel-Goren R, Levy Y, Amsterdam A, Alon R, Zakut R, Zick Y (Jul 2000). "Galectin-8 binding to integrins inhibits cell adhesion and induces apoptosis". Journal of Cell Science. 113 (13): 2385–97. doi:10.1242/jcs.113.13.2385. PMID10852818.
^Han DC, Rodriguez LG, Guan JL (Jan 2001). "Identification of a novel interaction between integrin beta1 and 14-3-3beta". Oncogene. 20 (3): 346–57. doi:10.1038/sj.onc.1204068. PMID11313964. S2CID7405925.
Further reading
Evans JP (Jul 2001). "Fertilin beta and other ADAMs as integrin ligands: insights into cell adhesion and fertilization". BioEssays. 23 (7): 628–39. doi:10.1002/bies.1088. PMID11462216. S2CID23712246.