Integrin beta-1 can exist as differentisoforms viaalternative splicing. Sixalternatively spliced variants have been found for this gene which encode five proteins with alternateC-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 theactincytoskeleton.[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 26amino acids of thecytoplasmic domain in exon 6 are retained and then succeeded by a 12amino acid stretch from an adjacentintronic region.[14] The integrin beta-1Bisoform appears to act as a dominant negative in that it inhibits cell adhesion.[15] A second integrin beta-1isoform, termed beta-1C, was described to have an additional 48amino acids appended to the 26amino acids in thecytoplasmic domain;[16] the function of this isoform was an inhibitory one onDNA synthesis in theG1 phase of thecell cycle.[17] The thirdisoform, termed beta-1D, is astriated muscle-specific isoform, which replaces the canonical beta-1Aisoform incardiac andskeletal muscle cells. Thisisoform is produced from splicing into a novel additional exon between exons 6 and 7. Thecytoplasmic domain of integrin beta-1D replaces the distal 21amino acids (present in integrin beta-1A) with an alternative stretch of 24amino acids (13 unique).[18][19]
In patients with sensitive-motorpolyneuropathy, levels ofintegrin alpha-7B, integrin beta-1D andagrin were significantly reduced nearly to undetectable levels; and this corresponded with lowermRNA 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.
^abSastry SK, Horwitz AF (Oct 1993). "Integrin cytoplasmic domains: mediators of cytoskeletal linkages and extra- and intracellular initiated transmembrane signaling".Current Opinion in Cell Biology.5 (5):819–31.doi:10.1016/0955-0674(93)90031-k.PMID8240826.
^Schwartz MA, Schaller MD, Ginsberg MH (1995). "Integrins: emerging paradigms of signal transduction".Annual Review of Cell and Developmental Biology.11:549–99.doi:10.1146/annurev.cb.11.110195.003001.PMID8689569.
^Altruda F, Cervella P, Tarone G, Botta C, Balzac F, Stefanuto G, Silengo L (Nov 1990). "A human integrin beta 1 subunit with a unique cytoplasmic domain generated by alternative mRNA processing".Gene.95 (2):261–6.doi:10.1016/0378-1119(90)90369-3.PMID2249781.
^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.Bibcode:1995BBRC..214..279Z.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.Bibcode:1996BBRC..222...13R.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.
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.