step steppke [Drosophila melanogaster (fruit fly)] - Gene

Summary

Official Symbol: stepprovided by FlyBase
Official Full Name: steppkeprovided by FlyBase
Primary source: FLYBASE:FBgn0086779
Locus tag: Dmel_CG11628
See related: AllianceGenome:FB:FBgn0086779
Gene type: protein coding
RefSeq status: REVIEWED
Organism: Drosophila melanogaster
Lineage: Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Hexapoda; Insecta; Pterygota; Neoptera; Endopterygota; Diptera; Brachycera; Muscomorpha; Ephydroidea; Drosophilidae; Drosophila; Sophophora
Also known as: CG11628; CG11633; CYH1; cytohesin/GRP1; Dmel\CG11628; GPH; Grp1; GRP1; GRP1/cytohesin 1; l(2)k08110; l(2)SH0323; l(2)SH2 0323; Step; stepk; Steppke
Summary: Enables phosphatidylinositol-3,4,5-trisphosphate binding activity and protein homodimerization activity. Involved in several processes, including dorsal closure; imaginal disc-derived wing vein specification; and positive regulation of signal transduction. Located in cell leading edge cell cortex and cleavage furrow. Colocalizes with adherens junction and contractile ring. Is expressed in several structures, including adult brain cell body rind; anterior endoderm; embryonic/larval midgut primordium; imaginal disc; and mesoderm. Orthologous to several human genes including CYTH1 (cytohesin 1). [provided by Alliance of Genome Resources, Dec 2024]
Orthologs: all
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Genomic context

Location:: 40A1-40A2; 2-54 cM

Exon count:: 12

Annotation release	Status	Assembly	Chr	Location
Release 6.54	current	Release 6 plus ISO1 MT (GCF_000001215.4)	2L	NT_033779.5 (21740041..21757466, complement)
Release 5.57	previous assembly	Release 5 (GCF_000001215.2)	2L	NT_033779.4 (21740041..21757466, complement)

Chromosome 2L - NT_033779.5 Genomic Context describing neighboring genes

Genomic regions, transcripts, and products

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Genomic Sequence:

Go to nucleotide: Graphics FASTA GenBank

Bibliography

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GeneRIFs: Gene References Into Functions

What's a GeneRIF?

This study is significant for defining a molecular mechanism that recruits Step to myosin-rich junctions for an established role in regulating actomyosin activity at these sites.
Title: Arf-GEF localization and function at myosin-rich adherens junctions via coiled-coil heterodimerization with an adaptor protein.
In Drosophila, protein localization, laser ablation, and genetic interaction studies indicate that the cytohesin Steppke reduces tissue tension by inhibiting actomyosin activity at adherens junctions. Without Steppke, embryogenesis fails, with epidermal distortions and tears resulting from myosin misregulation.
Title: An Actomyosin-Arf-GEF Negative Feedback Loop for Tissue Elongation under Stress.
It is proposed that a global distribution of Step normally sets an inhibitory threshold for Rho1 activity to restrict early cell formation to the posterior.
Title: Germ Cell Segregation from the Drosophila Soma Is Controlled by an Inhibitory Threshold Set by the Arf-GEF Steppke.
Steppke controls initial plasma membrane furrow ingression during the syncytial nuclear divisions and cellularization of the Drosophila embryo. Acting at the tips of ingressing furrows, Steppke promotes local endocytic events through its Arf-GEF activity.
Title: An Arf-GEF regulates antagonism between endocytosis and the cytoskeleton for Drosophila blastoderm development.
Step may be part of a larger signaling scaffold coordinating receptor tyrosine kinase-dependent MAPK activation
Title: The Drosophila Arf GEF Steppke controls MAPK activation in EGFR signaling.
identification of a new component of insulin signalling in Drosophila, the steppke gene (step)
Title: The cytohesin Steppke is essential for insulin signalling in Drosophila.

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Interactions

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Products	Interactant	Other Gene	Complex	Source	Pubs	Description

General gene information

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Homology

NCBI Orthologs

Orthologs from OrthoDB

mobile_element

Loc: c21743508-21743205 mobile_element_type = transposon:INE-1{}4930
Loc: c21744413-21744132 mobile_element_type = transposon:INE-1{}4931
Loc: c21746039-21745705 mobile_element_type = transposon:1360{}5473

Gene Ontology Provided by FlyBase

Function	Evidence Code	Pubs
enables guanyl-nucleotide exchange factor activity	IEA Inferred from Electronic Annotation more info
enables guanyl-nucleotide exchange factor activity	ISS Inferred from Sequence or Structural Similarity more info
enables phosphatidylinositol-3,4,5-trisphosphate binding	IDA Inferred from Direct Assay more info	PubMed
enables protein homodimerization activity	IPI Inferred from Physical Interaction more info	PubMed

Process	Evidence Code	Pubs
involved_in dorsal closure	IMP Inferred from Mutant Phenotype more info	PubMed
involved_in embryonic development via the syncytial blastoderm	IMP Inferred from Mutant Phenotype more info	PubMed
involved_in imaginal disc-derived wing vein specification	IMP Inferred from Mutant Phenotype more info	PubMed
involved_in positive regulation of ARF protein signal transduction	ISS Inferred from Sequence or Structural Similarity more info
involved_in positive regulation of ERK1 and ERK2 cascade	IMP Inferred from Mutant Phenotype more info	PubMed
involved_in positive regulation of epidermal growth factor receptor signaling pathway	IMP Inferred from Mutant Phenotype more info	PubMed
involved_in positive regulation of insulin receptor signaling pathway	IMP Inferred from Mutant Phenotype more info	PubMed
involved_in positive regulation of multicellular organism growth	IMP Inferred from Mutant Phenotype more info	PubMed
involved_in positive regulation of phosphatidylinositol 3-kinase/protein kinase B signal transduction	IMP Inferred from Mutant Phenotype more info	PubMed
involved_in regulation of ARF protein signal transduction	IEA Inferred from Electronic Annotation more info
involved_in regulation of actin cytoskeleton organization	IMP Inferred from Mutant Phenotype more info	PubMed
involved_in regulation of actomyosin structure organization	IMP Inferred from Mutant Phenotype more info	PubMed
involved_in regulation of endocytosis	IMP Inferred from Mutant Phenotype more info	PubMed

Component	Evidence Code	Pubs
located_in Golgi membrane	ISS Inferred from Sequence or Structural Similarity more info
colocalizes_with adherens junction	IDA Inferred from Direct Assay more info	PubMed
located_in cell cortex	IDA Inferred from Direct Assay more info	PubMed
located_in cell leading edge cell cortex	IDA Inferred from Direct Assay more info	PubMed
located_in cleavage furrow	IDA Inferred from Direct Assay more info	PubMed
colocalizes_with contractile ring	IDA Inferred from Direct Assay more info	PubMed
located_in cytosol	HDA more info	PubMed
located_in plasma membrane	IDA Inferred from Direct Assay more info	PubMed

General protein information

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Preferred Names: steppke

Names: CG11628-PA; CG11628-PC; CG11628-PD; CG11628-PE; general receptor for phosphoinositides 1; general receptor for phosphoinositides-1; lethal (2) SH0323; lethal (2) k08110; step-PA; step-PC; step-PD; step-PE

NCBI Reference Sequences (RefSeq)

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Genome Annotation

The following sections contain reference sequences that belong to a specific genome build. Explain

Reference assembly

Genomic

NT_033779.5 Reference assembly

Range

21740041..21757466 complement

Download

GenBank, FASTA, Sequence Viewer (Graphics)

mRNA and Protein(s)

NM_001273749.1 → NP_001260678.1 steppke, isoform E [Drosophila melanogaster]

See identical proteins and their annotated locations for NP_001260678.1

Status: REVIEWED

UniProtKB/TrEMBL

D5SHU0, Q0E8N2

Conserved Domains (3) summary

cd01252
Location:592 → 710

PH_GRP1-like; General Receptor for Phosphoinositides-1-like Pleckstrin homology (PH) domain

pfam00169
Location:596 → 708

PH; PH domain

pfam01369
Location:397 → 577

Sec7; Sec7 domain
NM_001042910.3 → NP_001036375.2 steppke, isoform C [Drosophila melanogaster]

See identical proteins and their annotated locations for NP_001036375.2

Status: REVIEWED

UniProtKB/TrEMBL

D5SHU0, Q0E8N2

Conserved Domains (3) summary

cd01252
Location:592 → 710

PH_GRP1-like; General Receptor for Phosphoinositides-1-like Pleckstrin homology (PH) domain

pfam00169
Location:596 → 708

PH; PH domain

pfam01369
Location:397 → 577

Sec7; Sec7 domain
NM_001169570.2 → NP_001163041.1 steppke, isoform D [Drosophila melanogaster]

See identical proteins and their annotated locations for NP_001163041.1

Status: REVIEWED

UniProtKB/TrEMBL

D5SHU0, Q0E8N2

Conserved Domains (3) summary

cd01252
Location:592 → 710

PH_GRP1-like; General Receptor for Phosphoinositides-1-like Pleckstrin homology (PH) domain

pfam00169
Location:596 → 708

PH; PH domain

pfam01369
Location:397 → 577

Sec7; Sec7 domain
NM_136276.4 → NP_610120.1 steppke, isoform A [Drosophila melanogaster]

See identical proteins and their annotated locations for NP_610120.1

Status: REVIEWED

UniProtKB/TrEMBL

Q8SYT7, Q9V9Q6

Related

FBpp0085264

Conserved Domains (2) summary

cd01252
Location:275 → 393

PH_GRP1-like; General Receptor for Phosphoinositides-1-like Pleckstrin homology (PH) domain

pfam01369
Location:78 → 260

Sec7; Sec7 domain