P34092 (MYOB_DICDI) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Myosin IB heavy chain

Gene names

Name:	myoB
Synonyms:	dmiB, myoA
ORF Names:	DDB_G0289117

Organism

Dictyostelium discoideum (Slime mold) [Reference proteome]

Taxonomic identifier

44689 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Amoebozoa › Mycetozoa › Dictyosteliida › Dictyostelium

Protein attributes

Sequence length	1111 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Myosin is a protein that binds to actin and has ATPase activity that is activated by actin. Myosin IB may have a role in chemotaxis and aggregation; it could serve to stabilize and even retract cortical structures, such as pseudopods and lamellopods. Involved in the whole cell motility of aggregation-stages cells. Overexpression results in significant decrease in the rate of cellular translocation and fluid-phase pinocytosis and abnormalities in the normal rearrangement of the actin cytoskeleton. Ref.9 Ref.10 Ref.13
Subunit structure	Myosin I heavy chain is single-headed. Dimer of a heavy and a light chain. Inability to self-assemble into filaments.
Subcellular location	Cell projection › pseudopodium. Cytoplasm › cell cortex. Note: Highest concentration just beneath the plasma membrane in the anterior pseudopod at the leading edge of the cell and at sites of cell-cell contact in both stationary and aggregation stage cells. Also found in macropinocytic structures. Ref.3 Ref.4 Ref.8 Ref.9
Developmental stage	Rises dramatically during early development. Ref.9
Domain	TH.1 binds directly to anionic phospholipid membranes; myosins I could therefore move actin relative to membranes and vice versa. TH.2 and SH3 bind tightly to F-actin; this together with the nucleotide-sensitive site in the head, allows single molecules of myosin I to cross-link actin filaments.
Disruption phenotype	Shows defects in pseudopod formation and translocation. Also shows slower speed of locomoting, aggregation-stage cells and significant reduction in initial rate of phagocytosis. myoB-/myoC- double mutant exhibits profound defects in growth, endocytosis and rearrangment of F-actin. Expression of the full-length myoB heavy chain in these cells fully rescues the double mutant defects. myoB-/myoD- double mutant exhibits reduction in the speed of whole cell translocation. myoB-/myoC-/myoD- triple mutant exhibits reduction in the speed of whole cell translocation. Ref.5 Ref.6 Ref.7 Ref.9 Ref.11
Sequence similarities	Contains 1 myosin head-like domain. Contains 1 SH3 domain.

Ontologies

Keywords
Biological process	Chemotaxis
Cellular component	Cell projection Cytoplasm
Domain	SH3 domain
Ligand	ATP-binding Actin-binding Nucleotide-binding
Molecular function	Motor protein Myosin
PTM	Phosphoprotein
Technical term	Complete proteome Direct protein sequencing Reference proteome
Gene Ontology (GO)
Biological_process	actin-myosin filament sliding Inferred from direct assay PubMed 18089562. Source: dictyBase chemotaxis Inferred from electronic annotation. Source: UniProtKB-KW exocytosis Inferred from expression pattern PubMed 21190565. Source: dictyBase phagocytosis Inferred from mutant phenotype Ref.9. Source: dictyBase phagosome reneutralization Inferred from mutant phenotype PubMed 22008230. Source: dictyBase regulation of post-lysosomal vacuole size Inferred from mutant phenotype PubMed 22008230. Source: dictyBase response to other organism Traceable author statement PubMed 14695060. Source: dictyBase
Cellular_component	actomyosin Inferred from direct assay PubMed 18089562. Source: dictyBase cell cortex Inferred from electronic annotation. Source: UniProtKB-SubCell cell leading edge Traceable author statement Ref.9. Source: dictyBase phagocytic cup lip Inferred from direct assay PubMed 20200225. Source: dictyBase phagocytic vesicle membrane Inferred from direct assay PubMed 21190565. Source: dictyBase pseudopodium Inferred from electronic annotation. Source: UniProtKB-SubCell unconventional myosin complex Inferred from direct assay PubMed 18089562. Source: dictyBase
Molecular_function	ATP binding Inferred from direct assay PubMed 18089562. Source: dictyBase actin filament binding Inferred from direct assay PubMed 18089562. Source: dictyBase actin-dependent ATPase activity Inferred from direct assay PubMed 18089562. Source: dictyBase microfilament motor activity Inferred from direct assay PubMed 18089562. Source: dictyBase myosin I head/neck binding Inferred from direct assay Ref.13. Source: dictyBase
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – 1111	1111	Myosin IB heavy chain		PRO_0000123366
Regions
	Domain	1 – 694	694	Myosin head-like
	Domain	1053 – 1111	59	SH3
	Nucleotide binding	102 – 109	8	ATP Potential
	Region	547 – 627	81	Actin-binding
	Region	695 – 921	227	Tail homology region 1 (TH.1)
	Compositional bias	922 – 1052	131	Ala/Gly/Pro-rich (TH.2)
	Compositional bias	951 – 1015	65	Asn-rich
	Compositional bias	955 – 965	11	Poly-Gln
Amino acid modifications
	Modified residue	332	1	Phosphoserine By similarity
Experimental info
	Mutagenesis	332	1	S → A: Fail to complement the null phenotype. Ref.11 Ref.13
	Mutagenesis	332	1	S → E: Forms a complex in the presence and absence of Ca(2+). Ref.11 Ref.13
	Sequence conflict	207	1	A → R in AAA33229. Ref.1
	Sequence conflict	365	1	R → K in AAA33229. Ref.1

Sequences

	Sequence		Length	Mass (Da)
	P34092 [UniParc]. Last modified December 4, 2007. Version 2. Checksum: B326A1DDF85B86AC	FASTA	1,111	124,257
	10 20 30 40 50 60 MSKKVQAKQG TDDLVMLPKV SEDEICENLK KRYMNDFIYT NIGPVLISVN PFRNLNNSGP 70 80 90 100 110 120 DFIEAYRGKH AQEVPPHVYQ LAESAYRAMK NDQENQCVII SGESGAGKTE AAKLIMGYVS 130 140 150 160 170 180 AISGSTEKVE YVKHVILESN PLLEAFGNAK TLRNNNSSRF GKYFEIQFDK AGDPVGGKIY 190 200 210 220 230 240 NYLLEKSRVV YQNPGERNFH IFYQLLAGAS AQEKRDYVLS SPESYYYLNQ SQCYTVDGIN 250 260 270 280 290 300 DVSDYAEVRQ AMDTIGLTAQ EQSDIIRIVA CVLHIGNIYF IEDDKGNAAI YDPNALELAA 310 320 330 340 350 360 SMLCIDSATL QNAILFRVIN TGGAGGAGNR RSTYNVPQNV EQANGTRDAL ARTIYDRMFS 370 380 390 400 410 420 WLVERVNQSL SYYKSPYQNV IGILDIFGFE IFEKNGFEQF CINFVNEKLQ QFFIELTLKA 430 440 450 460 470 480 EQEEYVREGI KWEPIKYFNN QIVCDLIEGK SPPGIFSLLD DICSTLHAQS TGTDQKFLEK 490 500 510 520 530 540 MAGIYDGHLH WRGMTGAFAI KHYAGEVTYE AEGFSDKNKD TLFFDLIEAI QCSKMPFLAS 550 560 570 580 590 600 LFNEDTGSLQ KKRPTTAGFK IKTSAGELMK ALSQCTPHYI RCIKPNETKK AKDWENSRVK 610 620 630 640 650 660 HQVQYLGLLE NVRVRRAGFA YRNTFDKVLK RYKKLSSKTW GIWGEWKGDA IEGCKTIFQD 670 680 690 700 710 720 MNLEAGQWQL GKTKVFIRHP ETVFLLEEAL DKKDFDCTAK IQKAFRNWKA KKHSLEQRAQ 730 740 750 760 770 780 IAHMFKDKKE RQRNSIDRKF TSDYIDFENQ FGLQEAMQNA HKKERVVFAD TVIKIDRRAK 790 800 810 820 830 840 QKNYEMVLTD QALYFVEKSI KKKVLVHTLI RRVGLREIKG VSISTLSDNV IVFHLPEHDQ 850 860 870 880 890 900 VIENDKKTEI IIVLVEYFKA IGGGSLNVQF SDRINYTLKK GEQKEISFQK SEQCPTLVVK 910 920 930 940 950 960 KGGKGLIGTI ASGLPSSTDS TPKNYNPNSM SQASSRPAPQ QSAGRGRGMP QGAGQPQPQQ 970 980 990 1000 1010 1020 PQQQQRPMPQ PQQGGGARPM PQPQQGGGAR PMGAPQQGGA PQQGAGRQLP QPTQQGGAPG 1030 1040 1050 1060 1070 1080 GRGAPMGRGA PGGGPAGAGG RPLPTVAKPA PQPSRPTAKA LYDYDASSTD ELSFKEGDII 1090 1100 1110 FIVQKDNGGW TQGELKSGQK GWAPTNYLQY N

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Dictyostelium discoideum contains a gene encoding a myosin I heavy chain." Jung G., Saxe C.L. III, Kimmel A.R., Hammer J.A. III Proc. Natl. Acad. Sci. U.S.A. 86:6186-6190(1989) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Strain: AX3.
[2]	"The genome of the social amoeba Dictyostelium discoideum." Eichinger L., Pachebat J.A., Gloeckner G., Rajandream M.A., Sucgang R., Berriman M., Song J., Olsen R., Szafranski K., Xu Q., Tunggal B., Kummerfeld S., Madera M., Konfortov B.A., Rivero F., Bankier A.T., Lehmann R., Hamlin N. , Davies R., Gaudet P., Fey P., Pilcher K., Chen G., Saunders D., Sodergren E.J., Davis P., Kerhornou A., Nie X., Hall N., Anjard C., Hemphill L., Bason N., Farbrother P., Desany B., Just E., Morio T., Rost R., Churcher C.M., Cooper J., Haydock S., van Driessche N., Cronin A., Goodhead I., Muzny D.M., Mourier T., Pain A., Lu M., Harper D., Lindsay R., Hauser H., James K.D., Quiles M., Madan Babu M., Saito T., Buchrieser C., Wardroper A., Felder M., Thangavelu M., Johnson D., Knights A., Loulseged H., Mungall K.L., Oliver K., Price C., Quail M.A., Urushihara H., Hernandez J., Rabbinowitsch E., Steffen D., Sanders M., Ma J., Kohara Y., Sharp S., Simmonds M.N., Spiegler S., Tivey A., Sugano S., White B., Walker D., Woodward J.R., Winckler T., Tanaka Y., Shaulsky G., Schleicher M., Weinstock G.M., Rosenthal A., Cox E.C., Chisholm R.L., Gibbs R.A., Loomis W.F., Platzer M., Kay R.R., Williams J.G., Dear P.H., Noegel A.A., Barrell B.G., Kuspa A. Nature 435:43-57(2005) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: AX4.
[3]	"Sequence, expression pattern, intracellular localization, and targeted disruption of the Dictyostelium myosin ID heavy chain isoform." Jung G., Fukui Y., Martin B., Hammer J.A. III J. Biol. Chem. 268:14981-14990(1993) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE OF 481-490; 656-666 AND 783-798, SUBCELLULAR LOCATION. Strain: AX3.
[4]	"Myosin I is located at the leading edges of locomoting Dictyostelium amoebae." Fukui Y., Lynch T.J., Brzeska H., Korn E.D. Nature 341:328-331(1989) [PubMed] [Europe PMC] [Abstract] Cited for: SUBCELLULAR LOCATION.
[5]	"Generation and characterization of Dictyostelium cells deficient in a myosin I heavy chain isoform." Jung G., Hammer J.A. III J. Cell Biol. 110:1955-1964(1990) [PubMed] [Europe PMC] [Abstract] Cited for: DISRUPTION PHENOTYPE.
[6]	"Myosin IB null mutants of Dictyostelium exhibit abnormalities in motility." Wessels D., Murray J., Jung G., Hammer J.A. III, Soll D.R. Cell Motil. Cytoskeleton 20:301-315(1991) [PubMed] [Europe PMC] [Abstract] Cited for: DISRUPTION PHENOTYPE.
[7]	"Dictyostelium myosin I double mutants exhibit conditional defects in pinocytosis." Novak K.D., Peterson M.D., Reedy M.C., Titus M.A. J. Cell Biol. 131:1205-1221(1995) [PubMed] [Europe PMC] [Abstract] Cited for: DISRUPTION PHENOTYPE.
[8]	"Localization of Dictyostelium myoB and myoD to filopodia and cell-cell contact sites using isoform-specific antibodies." Morita Y.S., Jung G., Hammer J.A. III, Fukui Y. Eur. J. Cell Biol. 71:371-379(1996) [PubMed] [Europe PMC] [Abstract] Cited for: SUBCELLULAR LOCATION.
[9]	"Dictyostelium mutants lacking multiple classic myosin I isoforms reveal combinations of shared and distinct functions." Jung G., Wu X., Hammer J.A. III J. Cell Biol. 133:305-323(1996) [PubMed] [Europe PMC] [Abstract] Cited for: SUBCELLULAR LOCATION, DISRUPTION PHENOTYPE, DEVELOPMENTAL STAGE, FUNCTION.
[10]	"Myosin I overexpression impairs cell migration." Novak K.D., Titus M.A. J. Cell Biol. 136:633-647(1997) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.
[11]	"The myosin I SH3 domain and TEDS rule phosphorylation site are required for in vivo function." Novak K.D., Titus M.A. Mol. Biol. Cell 9:75-88(1998) [PubMed] [Europe PMC] [Abstract] Cited for: DISRUPTION PHENOTYPE, MUTAGENESIS OF SER-332.
[12]	"Thirteen is enough: the myosins of Dictyostelium discoideum and their light chains." Kollmar M. BMC Genomics 7:183-183(2006) [PubMed] [Europe PMC] [Abstract] Cited for: NOMENCLATURE.
[13]	"Identification and characterization of an 8-kDa light chain associated with Dictyostelium discoideum MyoB, a class I myosin." Crawley S.W., de la Roche M.A., Lee S.F., Li Z., Chitayat S., Smith S.P., Cote G.P. J. Biol. Chem. 281:6307-6315(2006) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, MUTAGENESIS OF SER-332.
+	Additional computationally mapped references.

Cross-references

Sequence databases
EMBL GenBank DDBJ	M26037 Genomic DNA. Translation: AAA33229.1. AAFI02000130 Genomic DNA. Translation: EAL62866.1.
PIR	A33284.
RefSeq	XP_636382.1. XM_631290.1.
3D structure databases
ProteinModelPortal	P34092.
SMR	P34092. Positions 1059-1109.
ModBase	Search...
Protein-protein interaction databases
STRING	44689.DDB_0191351.
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Genome annotation databases
EnsemblProtists	DDB0191351; DDB0191351; DDB_G0289117.
GeneID	8626983.
KEGG	ddi:DDB_G0289117.
Organism-specific databases
dictyBase	DDB_G0289117. myoB.
Phylogenomic databases
eggNOG	COG5022.
KO	K10356.
OMA	LFRVINT.
ProtClustDB	CLSZ2429812.
Family and domain databases
InterPro	IPR001609. Myosin_head_motor_dom. IPR010926. Myosin_tail_2. IPR001452. SH3_domain. [Graphical view]
Pfam	PF00063. Myosin_head. 1 hit. PF06017. Myosin_TH1. 1 hit. PF00018. SH3_1. 1 hit. [Graphical view]
PRINTS	PR00193. MYOSINHEAVY. PR00452. SH3DOMAIN.
SMART	SM00242. MYSc. 1 hit. SM00326. SH3. 1 hit. [Graphical view]
SUPFAM	SSF50044. SH3. 1 hit.
PROSITE	PS50002. SH3. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

MYOB_DICDI

Accession

Primary (citable) accession number: P34092
Secondary accession number(s): Q54HY1

Entry history

Integrated into UniProtKB/Swiss-Prot:	February 1, 1994
Last sequence update:	December 4, 2007
Last modified:	May 1, 2013
This is version 96 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)