Alpha crystallin domain (ACD) found in mammalian HspB3, also known as heat-shock protein 27-like protein (HSPL27, 17-kDa) and similar proteins. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. HspB3 is expressed in adult skeletal muscle, smooth muscle, and heart, and in several other fetal tissues. In muscle cells HspB3 forms an oligomeric 150 kDa complex with myotonic dystrophy protein kinase-binding protein (MKBP/ HspB2), this complex may comprise one of two independent muscle-cell specific chaperone systems. The expression of HspB3 is induced during muscle differentiation controlled by the myogenic factor MyoD. HspB3 may also interact with Hsp22 (HspB8).

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 13929052  65 PPGEGKSRFQILLDVVQFLPEDIIIQTFEGWLLIKAQHGTRMDEHGFISRSFTRQYKLPDGVETKDLSAILCHDGILVVE 144
Cdd:cd06477   1 DQEEGKPMFQILLDVVQFRPEDIIIQVFEGWLLIKGQHGVRMDEHGFISRSFTRQYQLPDGVEHKDLSAMLCHDGILVVE 80

                ...
gi 13929052 145 VKD 147
Cdd:cd06477  81 TKD 83

Alpha crystallin domain (ACD) found in mammalian HspB3, also known as heat-shock protein 27-like protein (HSPL27, 17-kDa) and similar proteins. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. HspB3 is expressed in adult skeletal muscle, smooth muscle, and heart, and in several other fetal tissues. In muscle cells HspB3 forms an oligomeric 150 kDa complex with myotonic dystrophy protein kinase-binding protein (MKBP/ HspB2), this complex may comprise one of two independent muscle-cell specific chaperone systems. The expression of HspB3 is induced during muscle differentiation controlled by the myogenic factor MyoD. HspB3 may also interact with Hsp22 (HspB8).

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 13929052  65 PPGEGKSRFQILLDVVQFLPEDIIIQTFEGWLLIKAQHGTRMDEHGFISRSFTRQYKLPDGVETKDLSAILCHDGILVVE 144
Cdd:cd06477   1 DQEEGKPMFQILLDVVQFRPEDIIIQVFEGWLLIKGQHGVRMDEHGFISRSFTRQYQLPDGVEHKDLSAMLCHDGILVVE 80

                ...
gi 13929052 145 VKD 147
Cdd:cd06477  81 TKD 83

Small heat shock protein IbpA, HSP20 family [Posttranslational modification, protein turnover, chaperones];

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 13929052  68 EGKSRFQILLDVVQFLPEDIIIQTFEGWLLIKAQHGTRMDE-------HGFISRSFTRQYKLPDGVETKDLSAILcHDGI 140
Cdd:COG0071   6 ETDDAYVITADLPGVDKEDIDVTVEGNVLTISGERKEEEEEegenylrRERRYGSFERSFTLPDDVDVDKIEASY-ENGV 84

                ....*
gi 13929052 141 LVVEV 145
Cdd:COG0071  85 LTITL 89

Alpha crystallin domain (ACD) found in mammalian HspB3, also known as heat-shock protein 27-like protein (HSPL27, 17-kDa) and similar proteins. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. HspB3 is expressed in adult skeletal muscle, smooth muscle, and heart, and in several other fetal tissues. In muscle cells HspB3 forms an oligomeric 150 kDa complex with myotonic dystrophy protein kinase-binding protein (MKBP/ HspB2), this complex may comprise one of two independent muscle-cell specific chaperone systems. The expression of HspB3 is induced during muscle differentiation controlled by the myogenic factor MyoD. HspB3 may also interact with Hsp22 (HspB8).

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 13929052  65 PPGEGKSRFQILLDVVQFLPEDIIIQTFEGWLLIKAQHGTRMDEHGFISRSFTRQYKLPDGVETKDLSAILCHDGILVVE 144
Cdd:cd06477   1 DQEEGKPMFQILLDVVQFRPEDIIIQVFEGWLLIKGQHGVRMDEHGFISRSFTRQYQLPDGVEHKDLSAMLCHDGILVVE 80

                ...
gi 13929052 145 VKD 147
Cdd:cd06477  81 TKD 83

Alpha crystallin domain (ACD) found in mammalian small heat shock protein (sHsp) HspB2/heat shock 27kDa protein 2 and similar proteins. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. HspB2 is preferentially and constitutively expressed in skeletal muscle and heart. HspB2 shows homooligomeric activity and forms aggregates in muscle cytosol. Although its expression is not induced by heat shock, it redistributes to the insoluble fraction in response to heat shock. In the mouse heart, HspB2 plays a role in maintaining energetic balance, by protecting cardiac energetics during ischemia/reperfusion, and allowing for increased work during acute inotropic challenge. hHspB2 [previously also known as myotonic dystrophy protein kinase (DMPK) binding protein (MKBP)] is selectively up-regulated in skeletal muscles from myotonic dystrophy patients. The ACD of hHspB2 binds the DMPK kinase domain. In vitro, hHspB2 enhances the kinase activity of DMPK and confers thermoresistance. The hHspB2 gene lies less than 1kb from the 5 prime end of the related alphaB (HspB4)-crystallin gene, with the opposite transcription direction. These two genes may share regulatory elements for their expression.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 13929052  72 RFQILLDVVQFLPEDIIIQTFEGWLLIKAQHGTRMDEHGFISRSFTRQYKLPDGVETKDLSAILCHDGILVVE 144
Cdd:cd06476   8 KYQVFLDVCHFTPDEITVRTVDNLLEVSARHPQRMDRHGFVSREFTRTYILPMDVDPLLVRASLSHDGILCIQ 80

Alpha-crystallin domain found in alphaA-crystallin (HspB4), alphaB-crystallin (HspB5), and the small heat shock protein (sHsp) HspB6, also known as Hsp20. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. Alpha crystallin, an abundant protein in the mammalian lens, is a large (700 kDa) heteropolymer composed of HspB4 and HspB5, generally in a molar ratio of HspB4:HspB5 of 3:1. Only trace amounts of HspB4 are found in tissues other than the lens. HspB5 on the other hand is also expressed constitutively in other tissues including brain, heart, and type I and type IIa skeletal muscle fibers, and in several cancers including gliomas, renal cell carcinomas, basal-like and metaplastic breast carcinomas, and head and neck cancer. HspB5's functions include effects on the apoptotic pathway and on metastasis. Phosphorylation of HspB5 reduces its oligomerization and anti-apoptotic activities. HspB5 is protective in demyelinating disease such as multiple sclerosis (MS), being a negative regulator of inflammation. In early active MS lesions it is the most abundant gene transcript and an autoantigen, the immune response against it would disrupt its function and worsen inflammation and demyelination. Given as therapy for ongoing demyelinating disease it may counteract this effect. It is an autoantigen in the pathogenesis of various other inflammatory disorders including Lens-associated uveitis (LAU), and Behcet's disease. Mutations in HspB5 have been associated with diseases including dominant cataract and desmin-related myopathy. Mutations in HspB4 have been associated with Autosomal Dominant Congenital Cataract (ADCC). HspB6 (Hsp20) is ubiquitous and is involved in diverse functions including regulation of glucose transport and contraction of smooth muscle, in platelet aggregation, in cardioprotection, and in the prevention of apoptosis. It interacts with the universal scaffolding and adaptor protein 14-3-3, and also with the proapoptotic protein Bax.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 13929052  70 KSRFQILLDVVQFLPEDIIIQTFEGWLLIKAQHGTRMDEHGFISRSFTRQYKLPDGVETKDLSAILCHDGILVV 143
Cdd:cd06478   6 KDRFSVNLDVKHFSPEELSVKVLGDFVEIHGKHEERQDEHGFISREFHRRYRLPPGVDPAAITSSLSADGVLTI 79

Alpha-crystallin domain (ACD) of alpha-crystallin-type small(s) heat shock proteins (Hsps). sHsps are small stress induced proteins with monomeric masses between 12 -43 kDa, whose common feature is the Alpha-crystallin domain (ACD). sHsps are generally active as large oligomers consisting of multiple subunits, and are believed to be ATP-independent chaperones that prevent aggregation and are important in refolding in combination with other Hsps.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 13929052  68 EGKSRFQILLDVVQFLPEDIIIQTFEGWLLIKAQHGTRMDE------HGFISRSFTRQYKLPDGVETKDLSAILcHDGIL 141
Cdd:cd06464   4 ETDDAYVVEADLPGFKKEDIKVEVEDGVLTISGEREEEEEEeenylrRERSYGSFSRSFRLPEDVDPDKIKASL-ENGVL 82

                ....*
gi 13929052 142 VVEVK 146
Cdd:cd06464  83 TITLP 87

Hsp20/alpha crystallin family; Not only do small heat-shock-proteins occur in eukaryotes and prokaryotes but they have also now been shown to occur in cyanobacterial phages as well as their bacterial hosts.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 13929052    68 EGKSRFQILLDVVQFLPEDIIIQTFEGWLLIKAQH-GTRMDEHGFIS----RSFTRQYKLPDGVETKDLSAILcHDGILV 142
Cdd:pfam00011   4 EDEDAFEVRLDVPGFKPEELKVKVEDNRLLVKGEHeEEKEDDHGLRSersyGSFSRKFTLPENADPDKVKASL-KDGVLT 82

                  ...
gi 13929052   143 VEV 145
Cdd:pfam00011  83 VTV 85

Alpha-crystallin domain (ACD) found in mammalian 21.6 KDa small heat shock protein (sHsp) HspB8, also denoted as Hsp22 in humans, and similar proteins. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. A chaperone complex formed of HspB8 and Bag3 stimulates degradation of protein complexes by macroautophagy. HspB8 also forms complexes with Hsp27 (HspB1), MKBP (HspB2), HspB3, alphaB-crystallin (HspB5), Hsp20 (HspB6), and cvHsp (HspB7). These latter interactions may depend on phosphorylation of the respective partner sHsp. HspB8 may participate in the regulation of cell proliferation, cardiac hypertrophy, apoptosis, and carcinogenesis. Point mutations in HspB8 have been correlated with the development of several congenital neurological diseases, including Charcot Marie tooth disease and distal motor neuropathy type II.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 13929052  62 AETPPGEGKSRFQILLDVVQFLPEDIIIQTFEGWLLIKAQHGTRMDEHGFISRSFTRQYKLPDGVETKDLSAILCHDGIL 141
Cdd:cd06480   6 PRNPPPNSSEPWKVCVNVHSFKPEELTVKTKDGFVEVSGKHEEQQKEGGIVSKNFTKKIQLPPEVDPVTVFASLSPEGLL 85

                ...
gi 13929052 142 VVE 144
Cdd:cd06480  86 IIE 88

Alpha crystallin domain (ACD) found in mammalian small heat shock protein (sHsp) HspB7, also known as cardiovascular small heat shock protein (cvHsp), and similar proteins. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. HspB7 is a 25-kDa protein, preferentially expressed in heart and skeletal muscle. It binds the cytoskeleton protein alpha-filamin (also known as actin-binding protein 280). The expression of HspB7 is increased during rat muscle aging. Its expression is also modulated in obesity implicating this protein in this and related metabolic disorders. As the human gene encoding HspB7 is mapped to chromosome 1p36.23-p34.3 it is a positional candidate for several dystrophies and myopathies.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 13929052  73 FQILLDVVQFLPEDIIIQTFEGWLLIkaqHGTRMDEHGFISRSFTRQYKLPDGVETKDLSAILCHDGILVVEVK 146
Cdd:cd06479  10 YQFAVDVSDFSPEDIIVTTSNNQIEV---HAEKLASDGTVMNTFTHKCQLPEDVDPTSVSSSLGEDGTLTIKAR 80

Alpha-crystallin domain (ACD) found in Escherichia coli inclusion body-associated proteins IbpA and IbpB, and similar proteins. IbpA and IbpB are 16 kDa small heat shock proteins (sHsps). sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. IbpA and IbpB are produced during high-level production of various heterologous proteins, specifically human prorenin, renin and bovine insulin-like growth factor 2 (bIGF-2), and are strongly associated with inclusion bodies containing these heterologous proteins. IbpA and IbpB work as an integrated system to stabilize thermally aggregated proteins in a disaggregation competent state. The chaperone activity of IbpB is also significantly elevated as the temperature increases from normal to heat shock. The high temperature results in the disassociation of 2-3-MDa IbpB oligomers into smaller approximately 600-kDa structures. This elevated activity seen under heat shock conditions is retained for an extended period of time after the temperature is returned to normal. IbpA also forms multimers.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 13929052  69 GKSRFQILLDVVQFLPEDIIIQTFEGWLLIKAQHGTRMDE-----H-GFISRSFTRQYKLPDGVETKDLSAIlchDGILV 142
Cdd:cd06470   9 GENNYRITLAVAGFSEDDLEIEVENNQLTVTGKKADEENEereylHrGIAKRAFERSFNLADHVKVKGAELE---NGLLT 85

                ....
gi 13929052 143 VEVK 146
Cdd:cd06470  86 IDLE 89