Primary Information
BoMiProt ID	Bomi113
Protein Name	Butyrophilin subfamily 1 member A1
Organism	Bos taurus
Uniprot ID	P18892
Milk Fraction	Whey
Ref Sequence ID	NP_776933.1
Aminoacid Length	526
Molecular Weight	59277
FASTA Sequence	Download
Gene Name	BTN1A1
Gene ID	282157
Protein Existence Status	Reviewed: Experimental evidence at protein level
Secondary Information
Presence in other biological fluids/tissue/cells	Abundant in milk fat globule membrane,
Protein Function	butyrophilin mRNA correlates with the onset of milk fat secretion toward the end of pregnancy and is maintained throughout lactation; acts as a receptor, facilitating the interaction between cytoplasmic lipid droplets and the apical plasma membrane; the major component of a proteinaceous layer between the plasma membrane and lipid droplet surface; associated with complex immunological phenomena; regulate the function of T cells by engaging poorly defined receptors on both αβ and γδ T cells. BTN1A1 plays an important role in regulating LD synthesis via a mechanism involving membrane phospholipid composition.
Biochemical Properties	Associates with membranes via a single hydrophobic domain that is in the approximate middle of the sequence; Soluble forms of butyrophilin may accumulate between the fat droplet and the apical plasma membrane and become incorporated into the coat by association with other MFGM proteins or by self-association with the membrane-bound form of butyrophilin in the apical plasma membrane; incorporated into the protein coat by a massive rearrangement of the apical surface as the lipid droplets approach the plasma membrane; has motifs, especially hydrophobic domains that may interact with the surface of fat droplets in the apical cytoplasm
Significance in milk	protein associated in large amounts with MFGM and has function in the secretion of milk fat globules
PTMs	N linked glycosylation in the exoplasmic domain; presence of mannaose, galactose and N-acetylglucosamine; 3 potential N-glycosylation sites - 2 in the -NH2 terminal and 1 in -COOH terminal; Acylation with myristate, stearate, palmitate and oleate
Site(s) of PTM(s) N-glycosylation, O-glycosylation, Phosphorylation	>sp|P18892|BT1A1_BOVIN Butyrophilin subfamily 1 member A1 OS=Bos taurus OX=9913 GN=BTN1A1 PE=1 SV=2 MAVFPNSCLAGCLLIFILLQLPKLDSAPFDVIGPQEPILAVVGEDAELPC RLSPN*55VSAKGMELRWFREKVSPAVFVSREGQEQEGEEMAEYRGRVSLVED HIAEGSVAVRIQEVKASDDGEYRCFFRQDENYEEAIVHLKVAALGSDPHI SMKVQESGEIQLECTSVGWYPEPQVQWRTHRGEEFPSMSESRNPDEEGLF TVRASVIIRDSSMKN*215VSCCIRNLLLGQEKEVEVSIPASFFPRLTPWMVAV AVILVVLGLLTIGSIFFTWRLYKERSRQRRNEFSSKEKLLEELKWKRATL HAVDVTLDPDTAHPHLFLYEDSKSVRLEDSRQKLPEKPERFDSWPCVMGR EAFTSGRHYWEVEVGDRTDWAIGVCRENVMKKGFDPMTPENGFWAVELYG NGYWALTPLRTPLPLAGPPRRVGVFLDYESGDIFFYNMTDGSHIYTFSKA SFSGPLRPFFCLWSCGKKPLTICPVTDGLEGVMVVADAKDISKEIPLSPM GEDSASGDIETLHSKLIPLQPSQGVP
CATH	Matched CATH superfamily 2.60.40.10
Predicted Disorder Regions	185-191,497-526
DisProt Annotation
TM Helix Prediction	1TMH; (247-269)
PDB ID	4hh8,
Bibliography	1. Franke, W. W., Heid, H. W., Grund, C., Winter, S., Freudenstein, C., Schmid, E., Jarasch, E. D., and Keenan, T. W. (1981) Antibodies to the major insoluble milk fat globule membrane-associated protein: specific location in apical regions of lactating epithelial cells. J. Cell Biol. 89, 485–494. 2. Franke, W. W., Lüder, M. R., Kartenbeck, J., Zerban, H., and Keenan, T. W. (1976) Involvement of vesicle coat material in casein secretion and surface regeneration. J. Cell Biol. 69, 173–195. 3. Gavel, Y. and von Heijne, G. (1990) Sequence differences between glycosylated and non-glycosylated Asn-X-Thr/Ser acceptor sites: implications for protein engineering. Protein Eng. 3, 433–442. 4. Hirano, H., Parkhouse, B., Nicolson, G. L., Lennox, E. S., and Singer, S. J. (1972) Distribution of saccharide residues on membrane fragments from a myeloma-cell homogenate: its implications for membrane biogenesis. Proc. Natl. Acad. Sci. U. S. A. 69, 2945–2949. 5. Keenan, T. W., Heid, H. W., Stadler, J., Jarasch, E. d, and Franke, W. W. (1982) Tight attachment of fatty acids to proteins associated with milk lipid globule membrane. Eur. J. Cell Biol. 26, 270–276. 6. Freudenstein, C., Keenan, T. W., Eigel, W. N., Sasaki, M., Stadler, J., and Franke, W. W. (1979) Preparation and characterization of the inner coat material associated with fat globule membranes from bovine and human milk. Exp. Cell Res. 118, 277–294. 7.Han L, Zhang M, Xing Z, Coleman DN, Liang Y, Loor JJ, Yang G. Knockout of butyrophilin subfamily 1 member A1 (BTN1A1) alters lipid droplet formation and phospholipid composition in bovine mammary epithelial cells. J Anim Sci Biotechnol. 2020 Jul 3;11:72. doi: 10.1186/s40104-020-00479-6. PMID: 32637097; PMCID: PMC7333294.