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FLASH GENE

Symbol

IMPG2

contributors: mct - updated : 15-12-2020

HGNC name	interphotoreceptor matrix proteoglycan 2
HGNC id	18362

FLASH GENE DNA RNA EXPRESSION PROTEIN DISORDER ANIMAL & CELL MODELS

Corresponding disease	ARRP18 retinitis pigmentosa autosomal recessive, 18 VMD5 macular dystrophy, vitelliform, 5
Location	3q.12.3      Physical location : 100.945.287 - 101.039.419
Synonym name	interphotoreceptor matrix proteoglycan of 200 kDa
	spacrcan protein
	sialoprotein associated with cones and rods proteoglycan
	Spacrcan
Synonym symbol(s)	SPACRCAN, IPM200, RP56, VMD5

DNA

TYPE	functioning gene
STRUCTURE	98.03 kb     19 Exon(s)

10 Kb 5' upstream gene genomic sequence study

MAPPING

cloned

Y

linked

N

status

provisional

RNA

TRANSCRIPTS	type	messenger

identification nb exons type bp product Protein kDa AA specific expression Year Pubmed NM_016247 19 - 4464 NP_057331 138.5 1241 - 2001 11726612

EXPRESSION

Rna function	mRNA were expressed in the ganglion cell layer, the inner nuclear layer, and at the outer limiting membrane of retina (Escher 2008), and in pineal gland
Type

expressed in	(based on citations)
organ(s)	System Organ level 1 Organ level 2 Organ level 3 Organ level 4 Level Pubmed Species Stage Rna symbol Nervous brain diencephalon epithalamus pineal gland   Visual eye retina       Homo sapiens

tissue

System Tissue Tissue level 1 Tissue level 2 Level Pubmed Species Stage Rna symbol Epithelial secretory glandular endocrine   Nervous peripherous

cells

System Cell Pubmed Species Stage Rna symbol Visual cone photoreceptor Homo sapiens Visual rod photoreceptor Homo sapiens

cell lineage

cell lines

fluid/secretion

at STAGE

PROTEIN

PHYSICAL PROPERTIES

STRUCTURE

motifs/domains	a signal peptide, two SEA domains, and two EGF-like domains in the large extracellular N-terminal part of the protein (Bandah-Rozenfeld 2010)
	large central mucin domain
	three consensus sites for glucosaminoglycan attachment
	HA binding motifs (HABMs) are present in the deduced amino acid sequence and may be the sites of hyaluronan interaction (Chen 2004)
	a hydrophobic stretch of 23 amino acids near the C-terminal, potential transmembrane domain (Chen 2003)

conjugated

GlycoP

HOMOLOGY

intraspecies

homolog to IMPG1

Homologene

FAMILY

extracellular matrix glycoconjugates family

CATEGORY

structural protein

SUBCELLULAR LOCALIZATION	extracellular
	plasma membrane
text	extracellular matrix

basic FUNCTION	major proteoglycan involved in the organization of the insoluble interphotoreceptor matrix
	proteoglycan present in the interphotoreceptor matrix (IPM) of the retina that resists aqueous extraction through its binding to hyaluronan (Chen 2003)
	IMPG1 and IMPG2 have distinct pattern distributions in the IPM, and both cones and rods are surrounded by IMPG proteoglycans

CELLULAR PROCESS

PHYSIOLOGICAL PROCESS

PATHWAY

metabolism

signaling

sensory transduction/vision

a component

extracellular matrix compoment

INTERACTION

DNA

RNA

small molecule

protein

when IMPG2 is absent, IMPG1 cannot integrate into the interphotoreceptor matrix (IPM), leading to abnormal proteoglycan accumulation and visual deficits

cell & other

with IMPG1, bind to hyaluronan, a glycosaminoglycan molecule that is essential for the organization of the interphotoreceptor matrix (Bandah-Rozenfeld 2010)

REGULATION

ASSOCIATED DISORDERS

corresponding disease(s)

ARRP18 , VMD5

Susceptibility

Variant & Polymorphism

Candidate gene

Marker

Therapy target

ANIMAL & CELL MODELS

mice lacking both Impg1 and Impg2, regardless of sex, showed normal retinal structure and function, demonstrating that the aberrant Impg1 distribution is the main cause of the visual alterations observed in the absence of Impg2 )