This Human COCH overexpression lysate was created in HEK293 Cells and intented for use as a Western blot (WB) positive control. Purification of COCH protein (Cat: 11368-H07H) from the overexpression lysate was verified.
A DNA sequence encoding the mature form of human COCH (NP_001128530.1) (Glu 25-Gln 550) was expressed, with a polyhistidine tag at the N-terminus.
The recombinant full length of human COCH consists of 542 amino acids and has a calculated molecular mass of 59.4 kDa. In SDS-PAGE under reducing conditions, rhCOCH migrates as three bands with apparent molecular mass of 66, 48 and 18 kDa, corresponding to the alternative splicing isoforms.
Cell lysate was prepared by homogenization of the over-expressed cells in ice-cold modified RIPA Lysis Buffer with cocktail of protease inhibitors (Sigma). Cell debris was removed by centrifugation. Protein concentration was determined by Bradford assay (Bio-Rad protein assay, Microplate Standard assay). The cell lysate was boiled for 5 min in 1 x SDS loading buffer (50 mM Tris-HCl pH 6.8, 12.5% glycerol, 1% sodium dodecylsulfate, 0.01% bromophenol blue) containing 5% b-mercaptoethanol, and lyophilized.
Modified RIPA Lysis Buffer: 50 mM Tris-HCl pH 7.4, 150 mM NaCl, 1mM EDTA, 1% Triton X-100, 0.1% SDS, 1% Sodium deoxycholate, 1mM PMSF.
1. Centrifuge the tube for a few seconds and ensure the pellet at the bottom of the tube.
2. Re-dissolve the pellet using 200μL pure water and boil for 2-5 min.
1 X Sample Buffer (1 X modified RIPA buffer+1 X SDS loading buffer).
Stability & Storage
Store at 4℃ for up to twelve months from date of receipt. After re-dissolution, aliquot and store at -80℃ for up to twelve months. Avoid repeated freeze-thaw cycles.
Western Blot (WB)
Optimal dilutions/concentrations should be determined by the end user.
Human COCH-5B2 Overexpression Lysate;Human COCH5B2 Overexpression Lysate;Human DFNA9 Overexpression Lysate
Cochlin, also known as COCH-5B2 and COCH, is a secreted protein which contains one LCCL domain and two VWFA domains. It is an abundant inner ear protein expressed as multiple isoforms. Its function is also unknown, but it is suspected to be an extracellular matrix component. Cochlin and type II collagen are major constituents of the inner ear extracellular matrix, and Cochlin constitutes 70% of non-collagenous protein in the inner ear, the cochlin isoforms can be classified into three subgroups, p63s, p44s and p40s. The expression of cochlin is highly specific to the inner ear. Eleven missense mutation and one in-frame deletion have been reported in the COCH gene, causing hereditary progressive sensorineural hearing loss and vestibular dysfunction, deafness autosomal dominant type 9 (DFNA9). The co-localization of cochlin and type II collagen in the fibrillar substance in the subepithelial area indicate that cochlin may play a role in the structural homeostasis of the vestibule acting in concert with the fibrillar type II collagen bundles. Defects in COCH may contribute to Meniere disease which is an autosomal dominant disorder characterized by hearing loss associated with episodic vertigo.
Ikezono T, et al. (2005) Expression of cochlin in the vestibular organ of rats. ORL J Otorhinolaryngol Relat Spec. 67(5): 252-8.Shindo S, et al. (2008) Spatiotemporal expression of cochlin in the inner ear of rats during postnatal development. Neurosci Lett. 444(2): 148-52.Hosokawa S, et al. (2010) Ultrastructural localization of cochlin in the rat cochlear duct. Audiol Neurootol. 15(4): 247-53.