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Activin receptor type-1 Other names: Activin receptor type I, ACTR-I, Serine/threonine-protein kinase, receptor R1, SKR1, Activin receptor-like kinase 2, ALK-2, TGF-B superfamily receptor type I, TSR-I Genetic data Gene code: HUGO code:ACVR1 Protein Structure/Function Protein type: Serine/Threonine receptor kinase Domains: GS domain, TS domain, S/T domain Other Taxa expressing: Homo sapiens; homologs: many metazoan phyla Cell types: ubiquitous Subcellular localization: Plasma membrane Enzymatic Data Catalytic activity: ATP + (receptor-protein) = ADP + (receptor-protein) phosphate Cofactor(s): Magnesium or manganese Medical/Biotechnological data Diseases: Fibrodysplasia ossificans progressiva (FOP) Mendelian Inheritance in Man (OMIM) 135100

Activin receptor type 1B Other names: ACTR-IB, Serine/threonine-protein kinase receptor R2, SKR2, Activin receptor-like kinase 4, ALK-4 Genetic data Gene code: HUGO code: ACVR1B Protein Structure/Function Protein type: Serine/Threonine receptor kinase Domains: GS domain, TS domain, S/T domain Other Taxa expressing: Homo sapiens; homologs: many metazoan phyla Cell types: ubiquitous Subcellular localization: Plasma membrane Enzymatic Data Catalytic activity: ATP + (receptor-protein) = ADP + (receptor-protein) phosphate Cofactor(s): Magnesium or manganese Medical/Biotechnological data Diseases: Pancreatic Carcinoma

Activin receptor type 1C Other names: ACTR-IC, Activin receptor-like kinase 7, ALK-7 Genetic data Gene code: HUGO code:ACVR1C Protein Structure/Function Protein type: Serine/Threonine receptor kinase Domains: GS domain, TS domain, S/T domain Other Taxa expressing: Homo sapiens; homologs: many metazoan phyla Cell types: ubiquitous Subcellular localization: Plasma membrane Enzymatic Data Catalytic activity: ATP + (receptor-protein) = ADP + (receptor-protein) phosphate Cofactor(s): Magnesium or manganese

The Activin type I receptors transduce signals for a variety of members of the Transforming growth factor beta superfamily of ligands. This family of cytokines and hormones inlude activin, Anti-müllerian hormone (AMH), bone morphogenetic proteins (BMPs), and Nodal. They are involved in a host of physiological processes including, growth, cell differentiation, homeostasis, osteogenesis, apoptosis and many other functions. There are three type I Activin receptors:ACVR1, ACVR1B, and ACVR1C Each bind to a specific type II receptor-ligand complex.

Despite the large amount of processes that these ligands regulate, they all operate through essentially the same pathway: A ligand binds to a Type two receptor, which recruits and trans-phosphorylate a type I receptor. The type I receptor recruits a receptor regulated SMAD (R-SMAD) which it phosphorylates. The RSMAD then translocates to the nucleus where it functions as a transcription factor.

Contents 1 ACVR1 2 ACVR1B 3 ACVR1C 4 References

ACVR1 or ALK-2 transduces signals of BMPs. BMPs bind either ACVR2A/ACVR2B or a BMPR2 and then forms a complex with ACVR1. These go on to recruit the R-SMADs SMAD1, SMAD2, SMAD3 or SMAD6^[1] .

Identifiers
Symbol	ACVR1 ACVRLK2
HUGO	171
Entrez	90
OMIM	102576
RefSeq	NM_001105
UniProt	Q04771
Other data
EC number	2.7.11.30
Locus	Chr. 2 q23-q24

ACVR1B or ALK-4 acts as a transducer of Activin or activin like ligands (eg. Inhibin) signals. Activin binds to either ACVR2A or ACVR2B and then forms a complex with ACVR1B. These go on to recruit the R-SMADs SMAD2 or SMAD3^[1]. ACVR1B also transduces signals of nodal, GDF-1, and Vg1; however, unlike activin, they require other coreceptor molecules such as the protein Cripto^[2].

Identifiers
Symbol	ACVR1B ACVRLK4
HUGO	172
Entrez	91
OMIM	601300
RefSeq	NM_020328
UniProt	P36896
Other data
EC number	2.7.11.30
Locus	Chr. 12 q13

ACVR1C or ALK-7 transduces signals of Nodal. Nodal binds to ACVR2B and then forms a comlex with ACR1C. These go on to recruit the R-SMADs SMAD2 or SMAD3^[1].

Identifiers
Symbol	ACVR1C
HUGO	18123
Entrez	130399
OMIM	608981
RefSeq	NM_145259
UniProt	Q8NER5
Other data
Locus	Chr. 2 q24.2

1. ^ ^{a b c} Inman, GJ; Nicolas FJ, Callahan JF, Harling JD, Gaster LM, Reith AD, Laping NJ, Hill CS. (Jul 2002). "SB-431542 is a potent and specific inhibitor of transforming growth factor-beta superfamily type I activin receptor-like kinase (ALK) receptors ALK4, ALK5, and ALK7". Mol Pharmacol. 62 (1). Entrez PubMed 12065756. Retrieved on 2006-07-05. 
2. ^ Harrison, CA; Gray PC, Koerber SC, Fischer W, Vale W (Jun 2003). "Identification of a functional binding site for activin on the type I receptor ALK4". J Biol Chem. 278 (23). Entrez PubMed 12665502. Retrieved on 2006-07-05.