3h6a
From Proteopedia
Structure of the Calx-beta domain of integrin beta4 crystallized in the presence of calcium
Structural highlights
DiseaseITB4_HUMAN Defects in ITGB4 are a cause of epidermolysis bullosa letalis with pyloric atresia (EB-PA) [MIM:226730; also known as junctional epidermolysis bullosa with pyloric atresia (PA-JEB) or aplasia cutis congenita with gastrointestinal atresia. EB-PA is an autosomal recessive, frequently lethal, epidermolysis bullosa with variable involvement of skin, nails, mucosa, and with variable effects on the digestive system. It is characterized by mucocutaneous fragility, aplasia cutis congenita, and gastrointestinal atresia, which most commonly affects the pylorus. Pyloric atresia is a primary manifestation rather than a scarring process secondary to epidermolysis bullosa.[1] [2] [3] [4] [5] [6] [7] Defects in ITGB4 are a cause of generalized atrophic benign epidermolysis bullosa (GABEB) [MIM:226650. GABEB is a non-lethal, adult form of junctional epidermolysis bullosa characterized by life-long blistering of the skin, associated with hair and tooth abnormalities.[8] FunctionITB4_HUMAN Integrin alpha-6/beta-4 is a receptor for laminin. Plays a critical structural role in the hemidesmosome of epithelial cells. Is required for the regulation of keratinocyte polarity and motility.[9] [10] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe integrin alpha6beta4 is a receptor for laminins and provides stable adhesion of epithelial cells to the basement membranes. In addition, alpha6beta4 is important for keratinocyte migration during wound healing and favours the invasion of carcinomas into surrounding tissue. The cytoplasmic domain of the beta4 subunit is responsible for most of the intracellular interactions of the integrin; it contains four fibronectin type III domains and a Calx-beta motif. The crystal structure of the Calx-beta domain of beta4 was determined to 1.48 A resolution. The structure does not contain cations and biophysical data support the supposition that the Calx-beta domain of beta4 does not bind calcium. Comparison of the Calx-beta domain of beta4 with the calcium-binding domains of Na(+)/Ca(2+)-exchanger 1 reveals that in beta4 Arg1003 occupies a position equivalent to that of the calcium ions in the Na(+)/Ca(2+)-exchanger. By combining mutagenesis and thermally induced unfolding, it is shown that Arg1003 contributes to the stability of the Calx-beta domain. The structure of the Calx-beta domain is discussed in the context of the function and intracellular interactions of the integrin beta4 subunit and a putative functional site is proposed. Structure of the Calx-beta domain of the integrin beta4 subunit: insights into function and cation-independent stability.,Alonso-Garcia N, Ingles-Prieto A, Sonnenberg A, de Pereda JM Acta Crystallogr D Biol Crystallogr. 2009 Aug;65(Pt 8):858-71. Epub 2009, Jul 17. PMID:19622870[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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