KPNB1 Antibody (Rabbit mAb) [M6A17]

Application: Reactivity: Human, Mouse, Rat

Usage Information

Dilution
WB1:1000 IHC1:10000 IF1:50 FCM1:500

Application
WB, IHC, IF, FCM

Reactivity
Human, Mouse, Rat

Source
Rabbit Monoclonal Antibody

Storage Buffer
PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN3

Storage (from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years

Predicted MW Observed MW
97 kDa 97 kDa
^*Why do the predicted and actual molecular weights differ? The following reasons may explain differences between the predicted and actual protein molecular weight. Post-translational modifications(e.g., phosphorylation, glycosylation); Splice variants and isoforms; Relative charge; Multimerization.

Positive Control	Human testis tissue; Mouse testis tissue; Rat testis tissue; NIH/3T3 cells; C6 cells; HeLa cells; PC-12 cells; HepG2 cells; Caco-2 cells; SK-OV-3 cells
Negative Control

Datasheet & SDS

Biological Description

Specificity
KPNB1 Antibody (Rabbit mAb) [M6A17] detects endogenous levels of total KPNB1 protein.

Clone
M6A17

Synonym(s)
NTF97, KPNB1, Importin subunit beta-1, Importin-90, Karyopherin subunit beta-1, Nuclear factor p97, Pore targeting complex 97 kDa subunit, PTAC97

Background
KPNB1, importin beta-1, belongs to the karyopherin beta family of nuclear transport receptors and adopts a solenoid architecture built from nineteen tandem HEAT repeats, each repeat formed by a pair of antiparallel alpha helices connected by a loop, with the outward-facing A-helix positioned on the convex surface and the B-helix on the concave surface; nucleoporins engage the A-helix face while cargo proteins and adaptor molecules engage the B-helix face, giving the same solenoid scaffold two functionally distinct interaction surfaces. In the classical nuclear import pathway, importin alpha recognizes the nuclear localization signal on cargo proteins, and its importin-beta-binding domain then docks onto HEAT repeats spanning roughly residues 7 through 19 of KPNB1, assembling a ternary cargo-importin alpha-importin beta complex in the cytoplasm; KPNB1 can additionally function autonomously as a direct nuclear localization signal receptor without requiring importin alpha. Docking of this complex at the nuclear pore is mediated by direct binding between KPNB1 and phenylalanine-glycine-rich repeats, specifically the FxFG motif, displayed by nucleoporins; the crystal structure of the importin-beta N-terminal fragment bound to nucleoporin FxFG repeats shows the FxFG core engaging a primary binding site formed between the A-helices of HEAT repeats 5 and 6, with a secondary binding site located between repeats 6 and 7, and mutation of a single residue, Ile178, within this primary site measurably reduces both FxFG binding and nuclear protein import, directly linking this specific structural interface to transport function. KPNB1 is proposed to traverse the nuclear pore complex by sequentially engaging different nucleoporins positioned across the pore, each nucleoporin possessing progressively higher affinity for KPNB1 moving from the cytoplasmic to the nucleoplasmic face, effectively creating an affinity gradient that draws the cargo complex through the pore. Once inside the nucleus, RanGTP binds KPNB1 at a site that does not overlap with the FxFG binding sites, and this RanGTP engagement is proposed to trigger a conformational change that alters the FxFG binding site itself, releasing KPNB1 from the nucleoporin and dissociating the import complex to free the cargo in the nucleoplasm; the resulting RanGTP-KPNB1 complex then exits the nucleus and dissociates in the cytoplasm upon RanGTP hydrolysis, regenerating free KPNB1 for another import cycle. Because this HEAT-repeat-mediated FxFG engagement is structurally separable from RanGTP binding, the two binding events can occur and resolve sequentially within a single transport cycle. KPNB1 mediates nuclear import of cell-cycle regulators including cyclin D1, CDK4, cyclin A, and cyclin B1, and elevated KPNB1 expression supporting nuclear accumulation of these regulators is implicated across multiple cancer types.

Background

KPNB1, importin beta-1, belongs to the karyopherin beta family of nuclear transport receptors and adopts a solenoid architecture built from nineteen tandem HEAT repeats, each repeat formed by a pair of antiparallel alpha helices connected by a loop, with the outward-facing A-helix positioned on the convex surface and the B-helix on the concave surface; nucleoporins engage the A-helix face while cargo proteins and adaptor molecules engage the B-helix face, giving the same solenoid scaffold two functionally distinct interaction surfaces. In the classical nuclear import pathway, importin alpha recognizes the nuclear localization signal on cargo proteins, and its importin-beta-binding domain then docks onto HEAT repeats spanning roughly residues 7 through 19 of KPNB1, assembling a ternary cargo-importin alpha-importin beta complex in the cytoplasm; KPNB1 can additionally function autonomously as a direct nuclear localization signal receptor without requiring importin alpha. Docking of this complex at the nuclear pore is mediated by direct binding between KPNB1 and phenylalanine-glycine-rich repeats, specifically the FxFG motif, displayed by nucleoporins; the crystal structure of the importin-beta N-terminal fragment bound to nucleoporin FxFG repeats shows the FxFG core engaging a primary binding site formed between the A-helices of HEAT repeats 5 and 6, with a secondary binding site located between repeats 6 and 7, and mutation of a single residue, Ile178, within this primary site measurably reduces both FxFG binding and nuclear protein import, directly linking this specific structural interface to transport function. KPNB1 is proposed to traverse the nuclear pore complex by sequentially engaging different nucleoporins positioned across the pore, each nucleoporin possessing progressively higher affinity for KPNB1 moving from the cytoplasmic to the nucleoplasmic face, effectively creating an affinity gradient that draws the cargo complex through the pore. Once inside the nucleus, RanGTP binds KPNB1 at a site that does not overlap with the FxFG binding sites, and this RanGTP engagement is proposed to trigger a conformational change that alters the FxFG binding site itself, releasing KPNB1 from the nucleoporin and dissociating the import complex to free the cargo in the nucleoplasm; the resulting RanGTP-KPNB1 complex then exits the nucleus and dissociates in the cytoplasm upon RanGTP hydrolysis, regenerating free KPNB1 for another import cycle. Because this HEAT-repeat-mediated FxFG engagement is structurally separable from RanGTP binding, the two binding events can occur and resolve sequentially within a single transport cycle. KPNB1 mediates nuclear import of cell-cycle regulators including cyclin D1, CDK4, cyclin A, and cyclin B1, and elevated KPNB1 expression supporting nuclear accumulation of these regulators is implicated across multiple cancer types.

References
https://pubmed.ncbi.nlm.nih.gov/10929717/ https://pubmed.ncbi.nlm.nih.gov/37473981/

Protein Size (kDa)	PVDF Transfer Membrane Pore Size (μm)
< 10	0.22
10-20	0.22
20-30	0.45
30-45	0.45
45-70	0.45
80-100	0.45
100-140	0.45
> 140	0.45

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Protein Size (kDa)	Separating Gel Percentage
4-40	20%
12-45	15%
10-70	12.5%
15-100	10%
25-100	8%
60-210	5%