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1.A.8.11.3
Plasma membrane aquaporin 1, PIP1, PIP1;2, PIP1b, of 286 aas and 6 TMSs (Törnroth-Horsefield et al., 2006).  Transports H2O, H2O2 (Dynowski et al., 2008), O2 and CO2 (Zwiazek et al. 2017).  Forms active heterotetramers with PIP2;1 (1.A.8.11.4); down regulated under drought stress (Najafabadi et al., 2008); plays a role in salt tolerance (Li et al. 2018). Gated by H+, Ca2+, Mn2+ and Cd2+ (Verdoucq et al., 2008). The wheat orthologue has been described (Ayadi et al., 2011). 96% identical to PIP1;3. In Selaginella moellendorffii (Sm; spikemoss), SmPIP1;1 is retained in the ER while SmPIP2;1 is found in the plasma membrane but, upon co-expression, both isoforms are found in the plasma membrane as a heterotetramer, leading to a synergistic effect on water membrane permeability (Bienert et al. 2018). In some speices, PIP1 is inactive (e.g., in maize), but formation of a hetrotetramer with PIP2 allows transport (Vajpai et al. 2018). Transmembrane helices 2 and 3 determine the localization of plasma membrane PIPs (Wang et al. 2019). PIP1;2 from Malus domestica confers salt tolerance in transgenic Arabidopsis (Wang et al. 2022).

Accession Number:P61837
Protein Name:PIP1.1 aka PIP1a aka Aquaporin 1
Length:286
Molecular Weight:30689.00
Species:Arabidopsis thaliana (Mouse-ear cress) [3702]
Number of TMSs:6
Location1 / Topology2 / Orientation3: Cell membrane1 / Multi-pass membrane protein2
Substrate hydrogen peroxide, water, dioxygen, carbon dioxide

Cross database links:

RefSeq: NP_001078323.1    NP_191702.1   
Entrez Gene ID: 825316   
Pfam: PF00230   
KEGG: ath:AT3G61430   

Gene Ontology

GO:0009941 C:chloroplast envelope
GO:0016021 C:integral to membrane
GO:0005739 C:mitochondrion
GO:0005886 C:plasma membrane
GO:0005773 C:vacuole
GO:0015250 F:water channel activity
GO:0009414 P:response to water deprivation
GO:0055085 P:transmembrane transport
GO:0006833 P:water transport

References (5)

[1] “Water channels in the plant plasma membrane cloned by immunoselection from a mammalian expression system.”  Kammerloher W.et.al.   7920711
[2] “Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana.”  Salanoubat M.et.al.   11130713
[3] “Empirical analysis of transcriptional activity in the Arabidopsis genome.”  Yamada K.et.al.   14593172
[4] “From genome to function: the Arabidopsis aquaporins.”  Quigley F.et.al.   11806824
[5] “Methylation of aquaporins in plant plasma membrane.”  Santoni V.et.al.   16839310

External Searches:

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Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MEGKEEDVRV GANKFPERQP IGTSAQSDKD YKEPPPAPFF EPGELSSWSF WRAGIAEFIA 
61:	TFLFLYITVL TVMGVKRSPN MCASVGIQGI AWAFGGMIFA LVYCTAGISG GHINPAVTFG 
121:	LFLARKLSLT RALYYIVMQC LGAICGAGVV KGFQPKQYQA LGGGANTVAH GYTKGSGLGA 
181:	EIIGTFVLVY TVFSATDAKR NARDSHVPIL APLPIGFAVF LVHLATIPIT GTGINPARSL 
241:	GAAIIYNKDH SWDDHWVFWV GPFIGAALAA LYHVVVIRAI PFKSRS