CAPZB

CapZβ can exist as 3 unique β subunits, dependent on alternative splicing mechanisms.{{cite web | url = http://www.heartproteome.org/copa/ProteinInfo.aspx?QType=Protein%20ID&QValue=p47756 | title = F-actin-capping protein subunit beta | work = COPaKB }}{{cite journal | vauthors = Zong NC, Li H, Li H, Lam MP, Jimenez RC, Kim CS, Deng N, Kim AK, Choi JH, Zelaya I, Liem D, Meyer D, Odeberg J, Fang C, Lu HJ, Xu T, Weiss J, Duan H, Uhlen M, Yates JR, Apweiler R, Ge J, Hermjakob H, Ping P | title = Integration of cardiac proteome biology and medicine by a specialized knowledgebase | journal = Circulation Research | volume = 113 | issue = 9 | pages = 1043–53 | date = October 2013 | pmid = 23965338 | pmc = 4076475 | doi = 10.1161/CIRCRESAHA.113.301151 }} CapZβ1 is 31.4 kDa and 277 amino acids in length, CapZβ2 is 30.6 kDa and 272 amino acids in length, and CapZβ3 is 301 amino acids in length (N-terminal extension of 29 amino acids relative to the β2 subunit.{{cite journal | vauthors = von Bülow M, Rackwitz HR, Zimbelmann R, Franke WW | title = CP beta3, a novel isoform of an actin-binding protein, is a component of the cytoskeletal calyx of the mammalian sperm head | journal = Experimental Cell Research | volume = 233 | issue = 1 | pages = 216–24 | date = May 1997 | pmid = 9184090 | doi = 10.1006/excr.1997.3564 }}). In contrast, the 3 α subunits arise from distinct genes. CapZ is a heterodimer composed of an α and β subunit. In muscle, capping protein α1 subunit and β1 subunit are localized at the Z-disc, and form CapZ. CapZ interacts with α-actinin, nebulette, nebulin, HSC70. at the Z-disc.

CAPZB is a member of the F-actin capping protein family. This gene encodes the beta subunit of the barbed-end actin binding protein. The protein regulates growth of the actin filament by capping the barbed end of growing actin filaments.

CapZβ functions to cap actin filaments at barbed (+) ends, thus controlling the rate of G-actin polymerization to F-actin and corresponding filament length. CapZ works in concert with tropomodulin, which caps actin at pointed ends. In muscle, the interaction of CapZ with actin is critical during myofibrilogenesis, as administration of a CapZ monoclonal antibody or expression of CapZ mutant protein disrupts actin filament formation and assembly of myofibrils. Isoforms of the CapZβ (β1 and β2) have distinct functions, as CapZβ1 anchors actin at Z-discs and CapZβ2 at intercalated discs. Overexpression of CapZβ2 (and concomitant down-regulation of CapZβ1) in mice resulted in a diseased phenotype with stunted growth, irregular gait, labored breathing and juvenile lethality. Ultrastructural measurements showed severely disrupted myofibrillar architecture.{{cite journal | vauthors = Hart MC, Cooper JA | title = Vertebrate isoforms of actin capping protein beta have distinct functions In vivo | journal = The Journal of Cell Biology | volume = 147 | issue = 6 | pages = 1287–98 | date = December 1999 | pmid = 10601341 | doi = 10.1083/jcb.147.6.1287 | pmc=2168092}} A function of CapZβ in transducing protein kinase C signaling in cardiac myocytes was illuminated by a study in skinned cardiac fibers which demonstrated that partial, transgenic reduction of CapZβ attenuated the functional effect of protein kinase C on contraction and disturbed normal PKC isoform translocation patterns following phenylephrine or endothelin-1 treatment.{{cite journal | vauthors = Pyle WG, Hart MC, Cooper JA, Sumandea MP, de Tombe PP, Solaro RJ | title = Actin capping protein: an essential element in protein kinase signaling to the myofilaments | journal = Circulation Research | volume = 90 | issue = 12 | pages = 1299–306 | date = June 2002 | pmid = 12089068 | doi = 10.1161/01.res.0000024389.03152.22 | doi-access = free }} A later study showed that partial reduction of CapZβ was cardioprotective during ischemia-reperfusion injury, concomitant with altered PKC isoform translocation to myofilaments.{{cite journal | vauthors = Yang FH, Pyle WG | title = Reduced cardiac CapZ protein protects hearts against acute ischemia-reperfusion injury and enhances preconditioning | journal = Journal of Molecular and Cellular Cardiology | volume = 52 | issue = 3 | pages = 761–72 | date = March 2012 | pmid = 22155006 | doi = 10.1016/j.yjmcc.2011.11.013 }} Regarding the turnover of CapZβ, it was recently demonstrated that the protein turnover of CapZβ1 is in part regulated by the Bcl-2–associated athanogene, BAG3, through a mechanism involving the association between HSC70 and CapZβ1.

There is currently little to no data available on the relationship between the CAPZB gene and human disease.

{{reflist|33em|refs =

{{cite journal | vauthors = Casella JF, Craig SW, Maack DJ, Brown AE | title = Cap Z(36/32), a barbed end actin-capping protein, is a component of the Z-line of skeletal muscle | journal = The Journal of Cell Biology | volume = 105 | issue = 1 | pages = 371–9 | date = July 1987 | pmid = 3301868 | doi = 10.1083/jcb.105.1.371 | pmc=2114938}}

{{cite web | title = Entrez Gene: CAPZB capping protein (actin filament) muscle Z-line, beta| url = https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=832}}

{{cite journal | vauthors = Hart MC, Korshunova YO, Cooper JA | title = Vertebrates have conserved capping protein alpha isoforms with specific expression patterns | journal = Cell Motility and the Cytoskeleton | volume = 38 | issue = 2 | pages = 120–32 | year = 1997 | pmid = 9331217 | doi = 10.1002/(SICI)1097-0169(1997)38:2<120::AID-CM2>3.0.CO;2-B }}

{{cite journal | vauthors = Hart MC, Cooper JA | title = Vertebrate isoforms of actin capping protein beta have distinct functions In vivo | journal = The Journal of Cell Biology | volume = 147 | issue = 6 | pages = 1287–98 | date = December 1999 | pmid = 10601341 | doi = 10.1083/jcb.147.6.1287 | pmc=2168092}}

{{cite journal | vauthors = Hishiya A, Kitazawa T, Takayama S | title = BAG3 and Hsc70 interact with actin capping protein CapZ to maintain myofibrillar integrity under mechanical stress | journal = Circulation Research | volume = 107 | issue = 10 | pages = 1220–31 | date = November 2010 | pmid = 20884878 | doi = 10.1161/CIRCRESAHA.110.225649 | pmc=2980587}}

{{cite journal | vauthors = Papa I, Astier C, Kwiatek O, Raynaud F, Bonnal C, Lebart MC, Roustan C, Benyamin Y | title = Alpha actinin-CapZ, an anchoring complex for thin filaments in Z-line | journal = Journal of Muscle Research and Cell Motility | volume = 20 | issue = 2 | pages = 187–97 | date = February 1999 | pmid = 10412090 | doi = 10.1023/A:1005489319058 | s2cid = 25681698 }}

{{cite journal | vauthors = Schafer DA, Korshunova YO, Schroer TA, Cooper JA | title = Differential localization and sequence analysis of capping protein beta-subunit isoforms of vertebrates | journal = The Journal of Cell Biology | volume = 127 | issue = 2 | pages = 453–65 | date = October 1994 | pmid = 7929588 | doi = 10.1083/jcb.127.2.453 | pmc=2120197}}

{{cite journal | vauthors = Schafer DA, Hug C, Cooper JA | title = Inhibition of CapZ during myofibrillogenesis alters assembly of actin filaments | journal = The Journal of Cell Biology | volume = 128 | issue = 1–2 | pages = 61–70 | date = January 1995 | pmid = 7822423 | doi = 10.1083/jcb.128.1.61 | pmc=2120327}}

{{cite journal | vauthors = von Bülow M, Rackwitz HR, Zimbelmann R, Franke WW | title = CP beta3, a novel isoform of an actin-binding protein, is a component of the cytoskeletal calyx of the mammalian sperm head | journal = Experimental Cell Research | volume = 233 | issue = 1 | pages = 216–24 | date = May 1997 | pmid = 9184090 | doi = 10.1006/excr.1997.3564 }}

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• {{cite journal | vauthors = Barron-Casella EA, Torres MA, Scherer SW, Heng HH, Tsui LC, Casella JF | title = Sequence analysis and chromosomal localization of human Cap Z. Conserved residues within the actin-binding domain may link Cap Z to gelsolin/severin and profilin protein families | journal = The Journal of Biological Chemistry | volume = 270 | issue = 37 | pages = 21472–9 | date = September 1995 | pmid = 7665558 | doi = 10.1074/jbc.270.37.21472 | doi-access = free }}
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{{refend}}

• [http://www.heartproteome.org/copa/ProteinInfo.aspx?QType=Protein%20ID&QValue=P47756 Mass spectrometry characterization of human CAPZB at COPaKB]
• {{UCSC gene info|CAPZB}}

{{PDB Gallery|geneid=832}}

Category:Genes mutated in mice